diff --git a/COPYING b/COPYING new file mode 100644 --- /dev/null +++ b/COPYING @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. We, the Free Software Foundation, use the +GNU General Public License for most of our software; it applies also to +any other work released this way by its authors. You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +them if you wish), that you receive source code or can get it if you +want it, that you can change the software or use pieces of it in new +free programs, and that you know you can do these things. + + To protect your rights, we need to prevent others from denying you +these rights or asking you to surrender the rights. Therefore, you have +certain responsibilities if you distribute copies of the software, or if +you modify it: responsibilities to respect the freedom of others. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must pass on to the recipients the same +freedoms that you received. You must make sure that they, too, receive +or can get the source code. And you must show them these terms so they +know their rights. + + Developers that use the GNU GPL protect your rights with two steps: +(1) assert copyright on the software, and (2) offer you this License +giving you legal permission to copy, distribute and/or modify it. + + For the developers' and authors' protection, the GPL clearly explains +that there is no warranty for this free software. For both users' and +authors' sake, the GPL requires that modified versions be marked as +changed, so that their problems will not be attributed erroneously to +authors of previous versions. + + Some devices are designed to deny users access to install or run +modified versions of the software inside them, although the manufacturer +can do so. This is fundamentally incompatible with the aim of +protecting users' freedom to change the software. The systematic +pattern of such abuse occurs in the area of products for individuals to +use, which is precisely where it is most unacceptable. Therefore, we +have designed this version of the GPL to prohibit the practice for those +products. If such problems arise substantially in other domains, we +stand ready to extend this provision to those domains in future versions +of the GPL, as needed to protect the freedom of users. + + Finally, every program is threatened constantly by software patents. +States should not allow patents to restrict development and use of +software on general-purpose computers, but in those that do, we wish to +avoid the special danger that patents applied to a free program could +make it effectively proprietary. To prevent this, the GPL assures that +patents cannot be used to render the program non-free. + + The precise terms and conditions for copying, distribution and +modification follow. + + TERMS AND CONDITIONS + + 0. Definitions. + + "This License" refers to version 3 of the GNU General Public License. + + "Copyright" also means copyright-like laws that apply to other kinds of +works, such as semiconductor masks. + + "The Program" refers to any copyrightable work licensed under this +License. Each licensee is addressed as "you". "Licensees" and +"recipients" may be individuals or organizations. + + To "modify" a work means to copy from or adapt all or part of the work +in a fashion requiring copyright permission, other than the making of an +exact copy. The resulting work is called a "modified version" of the +earlier work or a work "based on" the earlier work. + + A "covered work" means either the unmodified Program or a work based +on the Program. + + To "propagate" a work means to do anything with it that, without +permission, would make you directly or secondarily liable for +infringement under applicable copyright law, except executing it on a +computer or modifying a private copy. Propagation includes copying, +distribution (with or without modification), making available to the +public, and in some countries other activities as well. + + To "convey" a work means any kind of propagation that enables other +parties to make or receive copies. Mere interaction with a user through +a computer network, with no transfer of a copy, is not conveying. + + An interactive user interface displays "Appropriate Legal Notices" +to the extent that it includes a convenient and prominently visible +feature that (1) displays an appropriate copyright notice, and (2) +tells the user that there is no warranty for the work (except to the +extent that warranties are provided), that licensees may convey the +work under this License, and how to view a copy of this License. If +the interface presents a list of user commands or options, such as a +menu, a prominent item in the list meets this criterion. + + 1. Source Code. + + The "source code" for a work means the preferred form of the work +for making modifications to it. "Object code" means any non-source +form of a work. + + A "Standard Interface" means an interface that either is an official +standard defined by a recognized standards body, or, in the case of +interfaces specified for a particular programming language, one that +is widely used among developers working in that language. + + The "System Libraries" of an executable work include anything, other +than the work as a whole, that (a) is included in the normal form of +packaging a Major Component, but which is not part of that Major +Component, and (b) serves only to enable use of the work with that +Major Component, or to implement a Standard Interface for which an +implementation is available to the public in source code form. A +"Major Component", in this context, means a major essential component +(kernel, window system, and so on) of the specific operating system +(if any) on which the executable work runs, or a compiler used to +produce the work, or an object code interpreter used to run it. + + The "Corresponding Source" for a work in object code form means all +the source code needed to generate, install, and (for an executable +work) run the object code and to modify the work, including scripts to +control those activities. However, it does not include the work's +System Libraries, or general-purpose tools or generally available free +programs which are used unmodified in performing those activities but +which are not part of the work. For example, Corresponding Source +includes interface definition files associated with source files for +the work, and the source code for shared libraries and dynamically +linked subprograms that the work is specifically designed to require, +such as by intimate data communication or control flow between those +subprograms and other parts of the work. + + The Corresponding Source need not include anything that users +can regenerate automatically from other parts of the Corresponding +Source. + + The Corresponding Source for a work in source code form is that +same work. + + 2. Basic Permissions. + + All rights granted under this License are granted for the term of +copyright on the Program, and are irrevocable provided the stated +conditions are met. This License explicitly affirms your unlimited +permission to run the unmodified Program. The output from running a +covered work is covered by this License only if the output, given its +content, constitutes a covered work. This License acknowledges your +rights of fair use or other equivalent, as provided by copyright law. + + You may make, run and propagate covered works that you do not +convey, without conditions so long as your license otherwise remains +in force. You may convey covered works to others for the sole purpose +of having them make modifications exclusively for you, or provide you +with facilities for running those works, provided that you comply with +the terms of this License in conveying all material for which you do +not control copyright. Those thus making or running the covered works +for you must do so exclusively on your behalf, under your direction +and control, on terms that prohibit them from making any copies of +your copyrighted material outside their relationship with you. + + Conveying under any other circumstances is permitted solely under +the conditions stated below. Sublicensing is not allowed; section 10 +makes it unnecessary. + + 3. Protecting Users' Legal Rights From Anti-Circumvention Law. + + No covered work shall be deemed part of an effective technological +measure under any applicable law fulfilling obligations under article +11 of the WIPO copyright treaty adopted on 20 December 1996, or +similar laws prohibiting or restricting circumvention of such +measures. + + When you convey a covered work, you waive any legal power to forbid +circumvention of technological measures to the extent such circumvention +is effected by exercising rights under this License with respect to +the covered work, and you disclaim any intention to limit operation or +modification of the work as a means of enforcing, against the work's +users, your or third parties' legal rights to forbid circumvention of +technological measures. + + 4. Conveying Verbatim Copies. + + You may convey verbatim copies of the Program's source code as you +receive it, in any medium, provided that you conspicuously and +appropriately publish on each copy an appropriate copyright notice; +keep intact all notices stating that this License and any +non-permissive terms added in accord with section 7 apply to the code; +keep intact all notices of the absence of any warranty; and give all +recipients a copy of this License along with the Program. + + You may charge any price or no price for each copy that you convey, +and you may offer support or warranty protection for a fee. + + 5. Conveying Modified Source Versions. + + You may convey a work based on the Program, or the modifications to +produce it from the Program, in the form of source code under the +terms of section 4, provided that you also meet all of these conditions: + + a) The work must carry prominent notices stating that you modified + it, and giving a relevant date. + + b) The work must carry prominent notices stating that it is + released under this License and any conditions added under section + 7. This requirement modifies the requirement in section 4 to + "keep intact all notices". + + c) You must license the entire work, as a whole, under this + License to anyone who comes into possession of a copy. This + License will therefore apply, along with any applicable section 7 + additional terms, to the whole of the work, and all its parts, + regardless of how they are packaged. This License gives no + permission to license the work in any other way, but it does not + invalidate such permission if you have separately received it. + + d) If the work has interactive user interfaces, each must display + Appropriate Legal Notices; however, if the Program has interactive + interfaces that do not display Appropriate Legal Notices, your + work need not make them do so. + + A compilation of a covered work with other separate and independent +works, which are not by their nature extensions of the covered work, +and which are not combined with it such as to form a larger program, +in or on a volume of a storage or distribution medium, is called an +"aggregate" if the compilation and its resulting copyright are not +used to limit the access or legal rights of the compilation's users +beyond what the individual works permit. Inclusion of a covered work +in an aggregate does not cause this License to apply to the other +parts of the aggregate. + + 6. Conveying Non-Source Forms. + + You may convey a covered work in object code form under the terms +of sections 4 and 5, provided that you also convey the +machine-readable Corresponding Source under the terms of this License, +in one of these ways: + + a) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by the + Corresponding Source fixed on a durable physical medium + customarily used for software interchange. + + b) Convey the object code in, or embodied in, a physical product + (including a physical distribution medium), accompanied by a + written offer, valid for at least three years and valid for as + long as you offer spare parts or customer support for that product + model, to give anyone who possesses the object code either (1) a + copy of the Corresponding Source for all the software in the + product that is covered by this License, on a durable physical + medium customarily used for software interchange, for a price no + more than your reasonable cost of physically performing this + conveying of source, or (2) access to copy the + Corresponding Source from a network server at no charge. + + c) Convey individual copies of the object code with a copy of the + written offer to provide the Corresponding Source. This + alternative is allowed only occasionally and noncommercially, and + only if you received the object code with such an offer, in accord + with subsection 6b. + + d) Convey the object code by offering access from a designated + place (gratis or for a charge), and offer equivalent access to the + Corresponding Source in the same way through the same place at no + further charge. You need not require recipients to copy the + Corresponding Source along with the object code. If the place to + copy the object code is a network server, the Corresponding Source + may be on a different server (operated by you or a third party) + that supports equivalent copying facilities, provided you maintain + clear directions next to the object code saying where to find the + Corresponding Source. Regardless of what server hosts the + Corresponding Source, you remain obligated to ensure that it is + available for as long as needed to satisfy these requirements. + + e) Convey the object code using peer-to-peer transmission, provided + you inform other peers where the object code and Corresponding + Source of the work are being offered to the general public at no + charge under subsection 6d. + + A separable portion of the object code, whose source code is excluded +from the Corresponding Source as a System Library, need not be +included in conveying the object code work. + + A "User Product" is either (1) a "consumer product", which means any +tangible personal property which is normally used for personal, family, +or household purposes, or (2) anything designed or sold for incorporation +into a dwelling. In determining whether a product is a consumer product, +doubtful cases shall be resolved in favor of coverage. For a particular +product received by a particular user, "normally used" refers to a +typical or common use of that class of product, regardless of the status +of the particular user or of the way in which the particular user +actually uses, or expects or is expected to use, the product. A product +is a consumer product regardless of whether the product has substantial +commercial, industrial or non-consumer uses, unless such uses represent +the only significant mode of use of the product. + + "Installation Information" for a User Product means any methods, +procedures, authorization keys, or other information required to install +and execute modified versions of a covered work in that User Product from +a modified version of its Corresponding Source. The information must +suffice to ensure that the continued functioning of the modified object +code is in no case prevented or interfered with solely because +modification has been made. + + If you convey an object code work under this section in, or with, or +specifically for use in, a User Product, and the conveying occurs as +part of a transaction in which the right of possession and use of the +User Product is transferred to the recipient in perpetuity or for a +fixed term (regardless of how the transaction is characterized), the +Corresponding Source conveyed under this section must be accompanied +by the Installation Information. But this requirement does not apply +if neither you nor any third party retains the ability to install +modified object code on the User Product (for example, the work has +been installed in ROM). + + The requirement to provide Installation Information does not include a +requirement to continue to provide support service, warranty, or updates +for a work that has been modified or installed by the recipient, or for +the User Product in which it has been modified or installed. Access to a +network may be denied when the modification itself materially and +adversely affects the operation of the network or violates the rules and +protocols for communication across the network. + + Corresponding Source conveyed, and Installation Information provided, +in accord with this section must be in a format that is publicly +documented (and with an implementation available to the public in +source code form), and must require no special password or key for +unpacking, reading or copying. + + 7. Additional Terms. + + "Additional permissions" are terms that supplement the terms of this +License by making exceptions from one or more of its conditions. +Additional permissions that are applicable to the entire Program shall +be treated as though they were included in this License, to the extent +that they are valid under applicable law. If additional permissions +apply only to part of the Program, that part may be used separately +under those permissions, but the entire Program remains governed by +this License without regard to the additional permissions. + + When you convey a copy of a covered work, you may at your option +remove any additional permissions from that copy, or from any part of +it. (Additional permissions may be written to require their own +removal in certain cases when you modify the work.) You may place +additional permissions on material, added by you to a covered work, +for which you have or can give appropriate copyright permission. + + Notwithstanding any other provision of this License, for material you +add to a covered work, you may (if authorized by the copyright holders of +that material) supplement the terms of this License with terms: + + a) Disclaiming warranty or limiting liability differently from the + terms of sections 15 and 16 of this License; or + + b) Requiring preservation of specified reasonable legal notices or + author attributions in that material or in the Appropriate Legal + Notices displayed by works containing it; or + + c) Prohibiting misrepresentation of the origin of that material, or + requiring that modified versions of such material be marked in + reasonable ways as different from the original version; or + + d) Limiting the use for publicity purposes of names of licensors or + authors of the material; or + + e) Declining to grant rights under trademark law for use of some + trade names, trademarks, or service marks; or + + f) Requiring indemnification of licensors and authors of that + material by anyone who conveys the material (or modified versions of + it) with contractual assumptions of liability to the recipient, for + any liability that these contractual assumptions directly impose on + those licensors and authors. + + All other non-permissive additional terms are considered "further +restrictions" within the meaning of section 10. If the Program as you +received it, or any part of it, contains a notice stating that it is +governed by this License along with a term that is a further +restriction, you may remove that term. If a license document contains +a further restriction but permits relicensing or conveying under this +License, you may add to a covered work material governed by the terms +of that license document, provided that the further restriction does +not survive such relicensing or conveying. + + If you add terms to a covered work in accord with this section, you +must place, in the relevant source files, a statement of the +additional terms that apply to those files, or a notice indicating +where to find the applicable terms. + + Additional terms, permissive or non-permissive, may be stated in the +form of a separately written license, or stated as exceptions; +the above requirements apply either way. + + 8. Termination. + + You may not propagate or modify a covered work except as expressly +provided under this License. Any attempt otherwise to propagate or +modify it is void, and will automatically terminate your rights under +this License (including any patent licenses granted under the third +paragraph of section 11). + + However, if you cease all violation of this License, then your +license from a particular copyright holder is reinstated (a) +provisionally, unless and until the copyright holder explicitly and +finally terminates your license, and (b) permanently, if the copyright +holder fails to notify you of the violation by some reasonable means +prior to 60 days after the cessation. + + Moreover, your license from a particular copyright holder is +reinstated permanently if the copyright holder notifies you of the +violation by some reasonable means, this is the first time you have +received notice of violation of this License (for any work) from that +copyright holder, and you cure the violation prior to 30 days after +your receipt of the notice. + + Termination of your rights under this section does not terminate the +licenses of parties who have received copies or rights from you under +this License. If your rights have been terminated and not permanently +reinstated, you do not qualify to receive new licenses for the same +material under section 10. + + 9. Acceptance Not Required for Having Copies. + + You are not required to accept this License in order to receive or +run a copy of the Program. Ancillary propagation of a covered work +occurring solely as a consequence of using peer-to-peer transmission +to receive a copy likewise does not require acceptance. However, +nothing other than this License grants you permission to propagate or +modify any covered work. These actions infringe copyright if you do +not accept this License. Therefore, by modifying or propagating a +covered work, you indicate your acceptance of this License to do so. + + 10. Automatic Licensing of Downstream Recipients. + + Each time you convey a covered work, the recipient automatically +receives a license from the original licensors, to run, modify and +propagate that work, subject to this License. You are not responsible +for enforcing compliance by third parties with this License. + + An "entity transaction" is a transaction transferring control of an +organization, or substantially all assets of one, or subdividing an +organization, or merging organizations. If propagation of a covered +work results from an entity transaction, each party to that +transaction who receives a copy of the work also receives whatever +licenses to the work the party's predecessor in interest had or could +give under the previous paragraph, plus a right to possession of the +Corresponding Source of the work from the predecessor in interest, if +the predecessor has it or can get it with reasonable efforts. + + You may not impose any further restrictions on the exercise of the +rights granted or affirmed under this License. For example, you may +not impose a license fee, royalty, or other charge for exercise of +rights granted under this License, and you may not initiate litigation +(including a cross-claim or counterclaim in a lawsuit) alleging that +any patent claim is infringed by making, using, selling, offering for +sale, or importing the Program or any portion of it. + + 11. Patents. + + A "contributor" is a copyright holder who authorizes use under this +License of the Program or a work on which the Program is based. The +work thus licensed is called the contributor's "contributor version". + + A contributor's "essential patent claims" are all patent claims +owned or controlled by the contributor, whether already acquired or +hereafter acquired, that would be infringed by some manner, permitted +by this License, of making, using, or selling its contributor version, +but do not include claims that would be infringed only as a +consequence of further modification of the contributor version. For +purposes of this definition, "control" includes the right to grant +patent sublicenses in a manner consistent with the requirements of +this License. + + Each contributor grants you a non-exclusive, worldwide, royalty-free +patent license under the contributor's essential patent claims, to +make, use, sell, offer for sale, import and otherwise run, modify and +propagate the contents of its contributor version. + + In the following three paragraphs, a "patent license" is any express +agreement or commitment, however denominated, not to enforce a patent +(such as an express permission to practice a patent or covenant not to +sue for patent infringement). To "grant" such a patent license to a +party means to make such an agreement or commitment not to enforce a +patent against the party. + + If you convey a covered work, knowingly relying on a patent license, +and the Corresponding Source of the work is not available for anyone +to copy, free of charge and under the terms of this License, through a +publicly available network server or other readily accessible means, +then you must either (1) cause the Corresponding Source to be so +available, or (2) arrange to deprive yourself of the benefit of the +patent license for this particular work, or (3) arrange, in a manner +consistent with the requirements of this License, to extend the patent +license to downstream recipients. "Knowingly relying" means you have +actual knowledge that, but for the patent license, your conveying the +covered work in a country, or your recipient's use of the covered work +in a country, would infringe one or more identifiable patents in that +country that you have reason to believe are valid. + + If, pursuant to or in connection with a single transaction or +arrangement, you convey, or propagate by procuring conveyance of, a +covered work, and grant a patent license to some of the parties +receiving the covered work authorizing them to use, propagate, modify +or convey a specific copy of the covered work, then the patent license +you grant is automatically extended to all recipients of the covered +work and works based on it. + + A patent license is "discriminatory" if it does not include within +the scope of its coverage, prohibits the exercise of, or is +conditioned on the non-exercise of one or more of the rights that are +specifically granted under this License. You may not convey a covered +work if you are a party to an arrangement with a third party that is +in the business of distributing software, under which you make payment +to the third party based on the extent of your activity of conveying +the work, and under which the third party grants, to any of the +parties who would receive the covered work from you, a discriminatory +patent license (a) in connection with copies of the covered work +conveyed by you (or copies made from those copies), or (b) primarily +for and in connection with specific products or compilations that +contain the covered work, unless you entered into that arrangement, +or that patent license was granted, prior to 28 March 2007. + + Nothing in this License shall be construed as excluding or limiting +any implied license or other defenses to infringement that may +otherwise be available to you under applicable patent law. + + 12. No Surrender of Others' Freedom. + + If conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot convey a +covered work so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you may +not convey it at all. For example, if you agree to terms that obligate you +to collect a royalty for further conveying from those to whom you convey +the Program, the only way you could satisfy both those terms and this +License would be to refrain entirely from conveying the Program. + + 13. Use with the GNU Affero General Public License. + + Notwithstanding any other provision of this License, you have +permission to link or combine any covered work with a work licensed +under version 3 of the GNU Affero General Public License into a single +combined work, and to convey the resulting work. The terms of this +License will continue to apply to the part which is the covered work, +but the special requirements of the GNU Affero General Public License, +section 13, concerning interaction through a network will apply to the +combination as such. + + 14. Revised Versions of this License. + + The Free Software Foundation may publish revised and/or new versions of +the GNU General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + + Each version is given a distinguishing version number. If the +Program specifies that a certain numbered version of the GNU General +Public License "or any later version" applies to it, you have the +option of following the terms and conditions either of that numbered +version or of any later version published by the Free Software +Foundation. If the Program does not specify a version number of the +GNU General Public License, you may choose any version ever published +by the Free Software Foundation. + + If the Program specifies that a proxy can decide which future +versions of the GNU General Public License can be used, that proxy's +public statement of acceptance of a version permanently authorizes you +to choose that version for the Program. + + Later license versions may give you additional or different +permissions. However, no additional obligations are imposed on any +author or copyright holder as a result of your choosing to follow a +later version. + + 15. Disclaimer of Warranty. + + THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY +APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT +HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY +OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, +THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM +IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF +ALL NECESSARY SERVICING, REPAIR OR CORRECTION. + + 16. Limitation of Liability. + + IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS +THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY +GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE +USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF +DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD +PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), +EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF +SUCH DAMAGES. + + 17. Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/Symantic/HTTP/Server.hs b/Symantic/HTTP/Server.hs new file mode 100644 --- /dev/null +++ b/Symantic/HTTP/Server.hs @@ -0,0 +1,857 @@ +{-# LANGUAGE GADTs #-} +{-# LANGUAGE ConstraintKinds #-} +{-# LANGUAGE DeriveFunctor #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE OverloadedStrings #-} +{-# LANGUAGE Rank2Types #-} +{-# LANGUAGE UndecidableInstances #-} +{-# OPTIONS_GHC -fno-warn-orphans #-} +-- | See +-- for an example of how to use this module. +module Symantic.HTTP.Server where + +import Control.Arrow (first) +import Control.Applicative (Applicative(..)) +import Control.Monad (Monad(..), unless, sequence, guard, (=<<)) +import Control.Monad.Trans.Class (MonadTrans(..)) +import Control.Monad.Trans.Except (ExceptT(..), runExceptT) +import Data.Bool +import Data.Either (Either(..)) +import Data.Eq (Eq(..)) +import Data.Function (($), (.), id) +import Data.Functor (Functor(..), (<$>)) +import Data.Int (Int) +import Data.Maybe (Maybe(..), fromMaybe, catMaybes) +import Data.Monoid (Monoid(..)) +import Data.Ord (Ord(..)) +import Data.Proxy (Proxy(..)) +import Data.Semigroup (Semigroup(..)) +import Data.String (String, IsString(..)) +import Data.Text (Text) +import System.IO (IO) +import Text.Show (Show(..)) +import qualified Control.Monad.Classes as MC +import qualified Control.Monad.Trans.Cont as C +import qualified Control.Monad.Trans.Reader as R +import qualified Control.Monad.Trans.State.Strict as S +import qualified Control.Monad.Trans.Writer.Strict as W +import qualified Data.ByteString as BS +import qualified Data.ByteString.Base64 as BS64 +import qualified Data.ByteString.Builder as BSB +import qualified Data.ByteString.Lazy as BSL +import qualified Data.List as List +import qualified Data.List.NonEmpty as NonEmpty +import qualified Data.Text.Encoding as Text +import qualified Data.Word8 as Word8 +import qualified Network.HTTP.Media as Media +import qualified Network.HTTP.Types as HTTP +import qualified Network.HTTP.Types.Header as HTTP +import qualified Network.Wai as Wai +import qualified Web.HttpApiData as Web + +import Symantic.HTTP + +-- * Type 'Server' +-- | @'Server' responses k@ is a recipe to produce an 'Wai.Application' +-- from arguments 'responses' (one per number of alternative routes), +-- separated by (':!:'). +-- +-- 'Server' is analogous to a scanf using a format customized for HTTP routing. +-- +-- The multiple 'ServerCheckT' monad transformers are there +-- to prioritize the errors according to the type of check raising them, +-- instead of the order of the combinators within an actual API specification. +newtype Server responses k = Server { unServer :: + S.StateT ServerState + (ServerCheckT [ServerErrorBody] -- 8th check, 400 error + (ServerCheckT [ServerErrorHeader] -- 7th check, 400 error + (ServerCheckT [ServerErrorQuery] -- 6th check, 400 error + (ServerCheckT [ServerErrorContentType] -- 5th check, 415 error + (ServerCheckT [ServerErrorAccept] -- 4th check, 406 error + (ServerCheckT [ServerErrorBasicAuth] -- 3rd check, 401 or 403 error + (ServerCheckT [ServerErrorMethod] -- 2nd check, 405 error + (ServerCheckT [ServerErrorPath] -- 1st check, 404 error + IO)))))))) + (responses -> k) + } deriving (Functor) + +-- | @'server' api responses@ returns a 'Wai.Application' +-- ready to be given to @Warp.run 80@. +server :: + Server responses (Response Server) -> + responses -> + Wai.Application +server (Server api) responses rq re = do + lrPath <- runServerChecks api $ ServerState rq + case lrPath of + Left err -> respondError HTTP.status404 [] err + Right lrMethod -> + case lrMethod of + Left err -> respondError HTTP.status405 [] err + Right lrBasicAuth -> + case lrBasicAuth of + Left err -> + case failError err of + [] -> respondError HTTP.status500 [] err + ServerErrorBasicAuth realm ba:_ -> + case ba of + BasicAuth_Unauthorized -> + respondError HTTP.status403 [] err + _ -> + respondError HTTP.status401 + [ ( HTTP.hWWWAuthenticate + , "Basic realm=\""<>Web.toHeader realm<>"\"" + ) ] err + Right lrAccept -> + case lrAccept of + Left err -> respondError HTTP.status406 [] err + Right lrContentType -> + case lrContentType of + Left err -> respondError HTTP.status415 [] err + Right lrQuery -> + case lrQuery of + Left err -> respondError HTTP.status400 [] err + Right lrHeader -> + case lrHeader of + Left err -> respondError HTTP.status400 [] err + Right lrBody -> + case lrBody of + Left err -> respondError HTTP.status400 [] err + Right (app, _st) -> + app responses rq re + where + respondError :: + Show err => + HTTP.Status -> + [(HTTP.HeaderName, HeaderValue)] -> + err -> IO Wai.ResponseReceived + respondError st hs err = + -- Trace.trace (show err) $ + re $ Wai.responseLBS st + ( (HTTP.hContentType, Media.renderHeader $ mediaType @PlainText) + : hs + ) (fromString $ show err) -- TODO: see what to return in the body + +-- | Unwrap the 'ExceptT' constructors to reach the 'Either' constructors. +runServerChecks :: + S.StateT ServerState (ExceptT e1 (ExceptT e2 (ExceptT e3 (ExceptT e4 (ExceptT e5 (ExceptT e6 (ExceptT e7 (ExceptT e8 IO)))))))) a -> + ServerState -> IO (Either e8 (Either e7 (Either e6 (Either e5 (Either e4 (Either e3 (Either e2 (Either e1 (a, ServerState))))))))) +runServerChecks s st = + runExceptT $ + runExceptT $ + runExceptT $ + runExceptT $ + runExceptT $ + runExceptT $ + runExceptT $ + runExceptT $ + S.runStateT s st + +-- ** Type 'ServerCheckT' +type ServerCheckT e = ExceptT (Fail e) + +-- *** Type 'RouteResult' +type RouteResult e = Either (Fail e) + +-- *** Type 'Fail' +data Fail e + = Fail ServerState e -- ^ Keep trying other paths. 404, 405 or 406. + | FailFatal !ServerState !e -- ^ Don't try other paths. + deriving (Show) +failState :: Fail e -> ServerState +failState (Fail st _) = st +failState (FailFatal st _) = st +failError :: Fail e -> e +failError (Fail _st e) = e +failError (FailFatal _st e) = e +instance Semigroup e => Semigroup (Fail e) where + Fail _ x <> Fail st y = Fail st (x<>y) + FailFatal _ x <> Fail st y = FailFatal st (x<>y) + Fail _ x <> FailFatal st y = FailFatal st (x<>y) + FailFatal _ x <> FailFatal st y = FailFatal st (x<>y) + +-- ** Type 'ServerState' +newtype ServerState = ServerState + { serverState_request :: Wai.Request + } +instance Show ServerState where + show _ = "ServerState" + +instance Cat Server where + (<.>) :: + forall a b c repr. + repr ~ Server => + repr a b -> repr b c -> repr a c + -- NOTE: if x fails, run y to see if it fails on a more prioritized check. + -- And if so, fail with y instead of x. + -- + -- This long spaghetti code may probably be avoided + -- with a more sophisticated 'Server' using a binary tree + -- instead of nested 'Either's, so that its 'Monad' instance + -- would do the right thing. But to my mind, + -- with the very few priorities of checks currently needed, + -- this is not worth the cognitive pain to design it. + -- Some copying/pasting/adapting will do for now. + Server x <.> Server y = Server $ + S.StateT $ \st -> do + xPath <- MC.exec @IO $ runServerChecks x st + case xPath of + Left xe -> MC.throw xe + Right xMethod -> + case xMethod of + Left xe -> do + yPath <- MC.exec @IO $ runServerChecks y (failState xe) + case yPath of + Left ye -> MC.throw ye + Right _yMethod -> MC.throw xe + Right xBasicAuth -> + case xBasicAuth of + Left xe -> do + yPath <- MC.exec @IO $ runServerChecks y (failState xe) + case yPath of + Left ye -> MC.throw ye + Right yMethod -> + case yMethod of + Left ye -> MC.throw ye + Right _yBasicAuth -> MC.throw xe + Right xAccept -> + case xAccept of + Left xe -> do + yPath <- MC.exec @IO $ runServerChecks y (failState xe) + case yPath of + Left ye -> MC.throw ye + Right yMethod -> + case yMethod of + Left ye -> MC.throw ye + Right yBasicAuth -> + case yBasicAuth of + Left ye -> MC.throw ye + Right _yAccept -> MC.throw xe + Right xContentType -> + case xContentType of + Left xe -> do + yPath <- MC.exec @IO $ runServerChecks y (failState xe) + case yPath of + Left ye -> MC.throw ye + Right yMethod -> + case yMethod of + Left ye -> MC.throw ye + Right yBasicAuth -> + case yBasicAuth of + Left ye -> MC.throw ye + Right yAccept -> + case yAccept of + Left ye -> MC.throw ye + Right _yQuery -> MC.throw xe + Right xQuery -> + case xQuery of + Left xe -> do + yPath <- MC.exec @IO $ runServerChecks y (failState xe) + case yPath of + Left ye -> MC.throw ye + Right yMethod -> + case yMethod of + Left ye -> MC.throw ye + Right yBasicAuth -> + case yBasicAuth of + Left ye -> MC.throw ye + Right yAccept -> + case yAccept of + Left ye -> MC.throw ye + Right yQuery -> + case yQuery of + Left ye -> MC.throw ye + Right _yHeader -> MC.throw xe + Right xHeader -> + case xHeader of + Left xe -> do + yPath <- MC.exec @IO $ runServerChecks y (failState xe) + case yPath of + Left ye -> MC.throw ye + Right yMethod -> + case yMethod of + Left ye -> MC.throw ye + Right yBasicAuth -> + case yBasicAuth of + Left ye -> MC.throw ye + Right yAccept -> + case yAccept of + Left ye -> MC.throw ye + Right yQuery -> + case yQuery of + Left ye -> MC.throw ye + Right yHeader -> + case yHeader of + Left ye -> MC.throw ye + Right _yBody -> MC.throw xe + Right xBody -> + case xBody of + Left xe -> do + yPath <- MC.exec @IO $ runServerChecks y (failState xe) + case yPath of + Left ye -> MC.throw ye + Right yMethod -> + case yMethod of + Left ye -> MC.throw ye + Right yBasicAuth -> + case yBasicAuth of + Left ye -> MC.throw ye + Right yAccept -> + case yAccept of + Left ye -> MC.throw ye + Right yQuery -> + case yQuery of + Left ye -> MC.throw ye + Right yHeader -> + case yHeader of + Left ye -> MC.throw ye + Right _yBody -> MC.throw xe + Right (a2b, st') -> + (first (. a2b)) <$> S.runStateT y st' +instance Alt Server where + Server x Server y = Server $ + S.StateT $ \st -> do + xPath <- MC.exec @IO $ runServerChecks x st + yPath <- MC.exec @IO $ runServerChecks y st + let fy = (first (\b2k (_a:!:b) -> b2k b) <$>) + case xPath of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left ye -> MC.throw (xe<>ye) + Right yMethod -> + fy $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ + return $ Right yMethod + Right xMethod -> + case xMethod of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left _ye -> MC.throw xe + Right yMethod -> + case yMethod of + Left ye -> MC.throw (xe<>ye) + Right yBasicAuth -> + fy $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ + return $ Right $ yBasicAuth + Right xBasicAuth -> + case xBasicAuth of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left _ye -> MC.throw xe + Right yMethod -> + case yMethod of + Left _ye -> MC.throw xe + Right yBasicAuth -> + case yBasicAuth of + Left ye -> MC.throw (xe<>ye) + Right yAccept -> + fy $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ + return $ Right yAccept + Right xAccept -> + case xAccept of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left _ye -> MC.throw xe + Right yMethod -> + case yMethod of + Left _ye -> MC.throw xe + Right yBasicAuth -> + case yBasicAuth of + Left _ye -> MC.throw xe + Right yAccept -> + case yAccept of + Left ye -> MC.throw (xe<>ye) + Right yContentType -> + fy $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ + return $ Right yContentType + Right xContentType -> + case xContentType of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left _ye -> MC.throw xe + Right yMethod -> + case yMethod of + Left _ye -> MC.throw xe + Right yBasicAuth -> + case yBasicAuth of + Left _ye -> MC.throw xe + Right yAccept -> + case yAccept of + Left _ye -> MC.throw xe + Right yContentType -> + case yContentType of + Left ye -> MC.throw (xe<>ye) + Right yQuery -> + fy $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ + return $ Right yQuery + Right xQuery -> + case xQuery of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left _ye -> MC.throw xe + Right yMethod -> + case yMethod of + Left _ye -> MC.throw xe + Right yBasicAuth -> + case yBasicAuth of + Left _ye -> MC.throw xe + Right yAccept -> + case yAccept of + Left _ye -> MC.throw xe + Right yContentType -> + case yContentType of + Left _ye -> MC.throw xe + Right yQuery -> + case yQuery of + Left ye -> MC.throw (xe<>ye) + Right yHeader -> + fy $ ExceptT $ ExceptT $ ExceptT $ + return $ Right yHeader + Right xHeader -> + case xHeader of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left _ye -> MC.throw xe + Right yMethod -> + case yMethod of + Left _ye -> MC.throw xe + Right yBasicAuth -> + case yBasicAuth of + Left _ye -> MC.throw xe + Right yAccept -> + case yAccept of + Left _ye -> MC.throw xe + Right yContentType -> + case yContentType of + Left _ye -> MC.throw xe + Right yQuery -> + case yQuery of + Left _ye -> MC.throw xe + Right yHeader -> + case yHeader of + Left ye -> MC.throw (xe<>ye) + Right yBody -> + fy $ ExceptT $ ExceptT $ + return $ Right yBody + Right xBody -> + case xBody of + Left xe | FailFatal{} <- xe -> MC.throw xe + | otherwise -> + case yPath of + Left _ye -> MC.throw xe + Right yMethod -> + case yMethod of + Left _ye -> MC.throw xe + Right yBasicAuth -> + case yBasicAuth of + Left _ye -> MC.throw xe + Right yAccept -> + case yAccept of + Left _ye -> MC.throw xe + Right yContentType -> + case yContentType of + Left _ye -> MC.throw xe + Right yQuery -> + case yQuery of + Left _ye -> MC.throw xe + Right yHeader -> + case yHeader of + Left _ye -> MC.throw xe + Right yBody -> + case yBody of + Left ye -> MC.throw (xe<>ye) + Right yr -> + fy $ ExceptT $ + return $ Right yr + Right xr -> + return $ first (\a2k (a:!:_b) -> a2k a) xr +instance Pro Server where + dimap a2b _b2a (Server r) = Server $ (\k b2k -> k (b2k . a2b)) <$> r + +-- ** Type 'ServerErrorPath' +newtype ServerErrorPath = ServerErrorPath Text + deriving (Eq, Show) +instance HTTP_Path Server where + type PathConstraint Server a = Web.FromHttpApiData a + segment expSegment = Server $ do + st@ServerState + { serverState_request = req + } <- S.get + case Wai.pathInfo req of + [] -> MC.throw $ Fail st [ServerErrorPath "empty path segment"] + [""] -> MC.throw $ Fail st [ServerErrorPath "trailing slash"] + curr:next + | curr /= expSegment -> + MC.throw $ Fail st [ServerErrorPath $ "expected: "<>expSegment<>" but got: "<>curr] + | otherwise -> do + S.put st + { serverState_request = req{ Wai.pathInfo = next } + } + return id + capture' :: forall a k. PathConstraint Server a => Name -> Server (a -> k) k + capture' name = Server $ do + st@ServerState + { serverState_request = req + } <- S.get + case Wai.pathInfo req of + [] -> MC.throw $ Fail st [ServerErrorPath "empty"] + [""] -> MC.throw $ Fail st [ServerErrorPath "trailing slash"] + curr:next -> + case Web.parseUrlPiece curr of + Left err -> MC.throw $ Fail st [ServerErrorPath $ "capture: "<>fromString name<>": "<>err] + Right a -> do + S.put st + { serverState_request = req{ Wai.pathInfo = next } + } + return ($ a) + captureAll = Server $ do + req <- S.gets serverState_request + return ($ Wai.pathInfo req) + +-- ** Type 'ServerErrorMethod' +data ServerErrorMethod = ServerErrorMethod + deriving (Eq, Show) + +-- | TODO: add its own error? +instance HTTP_Version Server where + version exp = Server $ do + st <- S.get + let got = Wai.httpVersion $ serverState_request st + if got == exp + then return id + else MC.throw $ Fail st [ServerErrorMethod] -- FIXME: ServerErrorVersion + +-- ** Type 'ServerErrorAccept' +data ServerErrorAccept = + ServerErrorAccept + MediaTypes + (Maybe (Either BS.ByteString MediaType)) + deriving (Eq, Show) + +-- ** Type 'ServerErrorContentType' +data ServerErrorContentType = ServerErrorContentType + deriving (Eq, Show) + +-- ** Type 'ServerErrorQuery' +newtype ServerErrorQuery = ServerErrorQuery Text + deriving (Show) +instance HTTP_Query Server where + type QueryConstraint Server a = Web.FromHttpApiData a + queryParams' name = Server $ do + st <- S.get + lift $ ExceptT $ ExceptT $ ExceptT $ return $ + let qs = Wai.queryString $ serverState_request st in + let vals = catMaybes $ (<$> qs) $ \(n,v) -> + if n == name + then Web.parseQueryParam . Text.decodeUtf8 <$> v + else Nothing in + case sequence vals of + Left err -> Left $ Fail st [ServerErrorQuery err] + Right vs -> Right $ Right $ Right ($ vs) + +-- ** Type 'ServerErrorHeader' +data ServerErrorHeader = ServerErrorHeader + deriving (Eq, Show) +instance HTTP_Header Server where + header n = Server $ do + st <- S.get + lift $ ExceptT $ ExceptT $ return $ + let hs = Wai.requestHeaders $ serverState_request st in + case List.lookup n hs of + Nothing -> Left $ Fail st [ServerErrorHeader] + Just v -> Right $ Right ($ v) + +-- ** Type 'ServerErrorBasicAuth' +data ServerErrorBasicAuth = + ServerErrorBasicAuth BasicAuthRealm (BasicAuth ()) + deriving (Show) + +-- ** Class 'ServerBasicAuth' +class ServerBasicAuth a where + serverBasicAuth :: + BasicAuthUser -> + BasicAuthPass -> + IO (BasicAuth a) + +-- | WARNING: current implementation of Basic Access Authentication +-- is not immune to certian kinds of timing attacks. +-- Decoding payloads does not take a fixed amount of time. +instance HTTP_BasicAuth Server where + type BasicAuthConstraint Server a = ServerBasicAuth a + type BasicAuthArgs Server a k = a -> k + basicAuth' realm = Server $ do + st <- S.get + let err e = MC.throw $ Fail st [ServerErrorBasicAuth realm e] + case decodeAuthorization $ serverState_request st of + Nothing -> err BasicAuth_BadPassword + Just (user, pass) -> do + MC.exec @IO (serverBasicAuth user pass) >>= \case + BasicAuth_BadPassword -> err BasicAuth_BadPassword + BasicAuth_NoSuchUser -> err BasicAuth_NoSuchUser + BasicAuth_Unauthorized -> err BasicAuth_Unauthorized + BasicAuth_Authorized a -> return ($ a) + where + -- | Find and decode an 'Authorization' header from the request as a Basic Auth + decodeAuthorization :: Wai.Request -> Maybe (BasicAuthUser, BasicAuthPass) + decodeAuthorization req = do + hAuthorization <- List.lookup "Authorization" $ Wai.requestHeaders req + let (basic, rest) = BS.break Word8.isSpace hAuthorization + guard (BS.map Word8.toLower basic == "basic") + let decoded = BS64.decodeLenient (BS.dropWhile Word8.isSpace rest) + let (user, colon_pass) = BS.break (== Word8._colon) decoded + (_, pass) <- BS.uncons colon_pass + return (Text.decodeUtf8 user, Text.decodeUtf8 pass) + +-- ** Type 'ServerErrorBody' +newtype ServerErrorBody = ServerErrorBody String + deriving (Eq, Show) + +-- *** Type 'ServerBodyArg' +newtype ServerBodyArg (ts::[*]) a = ServerBodyArg a + +instance HTTP_Body Server where + type BodyConstraint Server a ts = MimeTypes ts (MimeDecodable a) + type BodyArg Server a ts = ServerBodyArg ts a + body' :: + forall a ts k repr. + BodyConstraint repr a ts => + repr ~ Server => + repr (BodyArg repr a ts -> k) k + body'= Server $ do + st <- S.get + lift $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ do + let hs = Wai.requestHeaders $ serverState_request st + let reqContentType = + -- DOC: http://www.w3.org/Protocols/rfc2616/rfc2616-sec7.html#sec7.2.1 + -- DOC: http://www.w3.org/2001/tag/2002/0129-mime + fromMaybe "application/octet-stream" $ + List.lookup HTTP.hContentType hs + case matchContent @ts @(MimeDecodable a) reqContentType of + Nothing -> return $ Left $ Fail st [ServerErrorContentType] + Just (MimeType mt) -> do + bodyBS <- MC.exec @IO $ Wai.requestBody $ serverState_request st + return $ Right $ Right $ Right $ + -- NOTE: delay 'mimeDecode' after all checks + case mimeDecode mt $ BSL.fromStrict bodyBS of + Left err -> Left $ Fail st [ServerErrorBody err] + Right a -> Right ($ ServerBodyArg a) + +-- *** Type 'ServerBodyStreamArg' +newtype ServerBodyStreamArg as (ts::[*]) framing + = ServerBodyStreamArg as +instance HTTP_BodyStream Server where + type BodyStreamConstraint Server as ts framing = + ( FramingDecode framing as + , MC.MonadExec IO (FramingMonad as) + , MimeTypes ts (MimeDecodable (FramingYield as)) + ) + type BodyStreamArg Server as ts framing = + ServerBodyStreamArg as ts framing + bodyStream' :: + forall as ts framing k repr. + BodyStreamConstraint repr as ts framing => + repr ~ Server => + repr (BodyStreamArg repr as ts framing -> k) k + bodyStream'= Server $ do + st <- S.get + lift $ ExceptT $ ExceptT $ ExceptT $ ExceptT $ do + let hs = Wai.requestHeaders $ serverState_request st + let reqContentType = + -- DOC: http://www.w3.org/Protocols/rfc2616/rfc2616-sec7.html#sec7.2.1 + -- DOC: http://www.w3.org/2001/tag/2002/0129-mime + fromMaybe "application/octet-stream" $ + List.lookup HTTP.hContentType hs + case matchContent @ts @(MimeDecodable (FramingYield as)) reqContentType of + Nothing -> return $ Left $ Fail st [ServerErrorContentType] + Just (MimeType mt) -> do + let bodyBS = Wai.requestBody $ serverState_request st + return $ Right $ Right $ Right $ + Right ($ ServerBodyStreamArg $ + framingDecode (Proxy @framing) (mimeDecode mt) $ + MC.exec @IO bodyBS + ) + +-- * Type 'ServerResponse' +-- | A continuation for |server|'s users to respond. +-- +-- This newtype has two uses : +-- * Carrying the 'ts' type variable to 'server'. +-- * Providing a 'return' for the simple response case +-- of 'HTTP.status200' and no extra headers. +newtype ServerRes (ts::[*]) m a + = ServerResponse + { unServerResponse :: m a + } deriving (Functor, Applicative, Monad) +type ServerResponse ts m = ServerRes ts + (R.ReaderT Wai.Request + (W.WriterT HTTP.ResponseHeaders + (W.WriterT HTTP.Status + (C.ContT Wai.Response m)))) +instance MonadTrans (ServerRes ts) where + lift = ServerResponse +-- | All supported effects are handled by nested 'Monad's. +type instance MC.CanDo (ServerResponse ts m) eff = 'False +type instance MC.CanDo (C.ContT ts m) (MC.EffExec eff) = 'False + +instance HTTP_Response Server where + type ResponseConstraint Server a ts = MimeTypes ts (MimeEncodable a) + type ResponseArgs Server a ts = ServerResponse ts IO a + type Response Server = + Wai.Request -> + (Wai.Response -> IO Wai.ResponseReceived) -> + IO Wai.ResponseReceived + response :: + forall a ts repr. + ResponseConstraint repr a ts => + repr ~ Server => + HTTP.Method -> + repr (ResponseArgs repr a ts) + (Response repr) + response expMethod = Server $ do + st@ServerState + { serverState_request = req + } <- S.get + + -- Check the path has been fully consumed + unless (List.null $ Wai.pathInfo req) $ + MC.throw $ Fail st [ServerErrorPath "path is longer"] + + -- Check the method + let reqMethod = Wai.requestMethod $ serverState_request st + unless (reqMethod == expMethod + || reqMethod == HTTP.methodHead + && expMethod == HTTP.methodGet) $ + MC.throw $ Fail st [ServerErrorMethod] + + -- Check the Accept header + let reqHeaders = Wai.requestHeaders $ serverState_request st + MimeType reqAccept <- do + case List.lookup HTTP.hAccept reqHeaders of + Nothing -> + return $ NonEmpty.head $ mimeTypes @ts @(MimeEncodable a) + Just h -> + case matchAccept @ts @(MimeEncodable a) h of + Nothing -> MC.throw $ Fail st [ServerErrorAccept (mediaTypes @ts @(MimeEncodable a)) (Just (Left h))] + Just mt -> return mt + + return $ \(ServerResponse k) rq re -> re =<< do + C.runContT (W.runWriterT $ W.runWriterT $ R.runReaderT k rq) $ \((a,hs),sta) -> + return{-IO-} $ + Wai.responseLBS sta + ((HTTP.hContentType, Media.renderHeader $ mediaTypeFor reqAccept):hs) + (if reqMethod == HTTP.methodHead + then "" + else mimeEncode reqAccept a) + +-- * Type 'ServerResponseStream' +-- +-- This newtype has three uses : +-- * Carrying the 'framing' type variable to 'server'. +-- * Carrying the 'ts' type variable to 'server'. +-- * Providing a 'return' for the simple response case +-- of 'HTTP.status200' and no extra headers. +newtype ServerResStream framing (ts::[*]) m as + = ServerResponseStream + { unServerResponseStream :: m as + } deriving (Functor, Applicative, Monad) +instance MonadTrans (ServerResStream framing ts) where + lift = ServerResponseStream +type ServerResponseStream framing ts m = ServerResStream framing ts + (R.ReaderT Wai.Request + (W.WriterT HTTP.ResponseHeaders + (W.WriterT HTTP.Status + (C.ContT Wai.Response m)))) +-- | All supported effects are handled by nested 'Monad's. +type instance MC.CanDo (ServerResponseStream framing ts m) eff = 'False + +instance HTTP_ResponseStream Server where + type ResponseStreamConstraint Server as ts framing = + ( FramingEncode framing as + , MimeTypes ts (MimeEncodable (FramingYield as)) + ) + type ResponseStreamArgs Server as ts framing = + ServerResponseStream framing ts IO as + type ResponseStream Server = + Wai.Request -> + (Wai.Response -> IO Wai.ResponseReceived) -> + IO Wai.ResponseReceived + responseStream :: + forall as ts framing repr. + ResponseStreamConstraint repr as ts framing => + repr ~ Server => + HTTP.Method -> + repr (ResponseStreamArgs repr as ts framing) + (ResponseStream repr) + responseStream expMethod = Server $ do + st@ServerState + { serverState_request = req + } <- S.get + + -- Check the path has been fully consumed + unless (List.null $ Wai.pathInfo req) $ + MC.throw $ Fail st [ServerErrorPath "path is longer"] + + -- Check the method + let reqMethod = Wai.requestMethod $ serverState_request st + unless (reqMethod == expMethod + || reqMethod == HTTP.methodHead + && expMethod == HTTP.methodGet) $ + MC.throw $ Fail st [ServerErrorMethod] + + -- Check the Accept header + let reqHeaders = Wai.requestHeaders $ serverState_request st + MimeType reqAccept <- do + case List.lookup HTTP.hAccept reqHeaders of + Nothing -> + return $ NonEmpty.head $ mimeTypes @ts @(MimeEncodable (FramingYield as)) + Just h -> + case matchAccept @ts @(MimeEncodable (FramingYield as)) h of + Nothing -> MC.throw $ Fail st [ServerErrorAccept (mediaTypes @ts @(MimeEncodable (FramingYield as))) (Just (Left h))] + Just mt -> return mt + + return $ \(ServerResponseStream k) rq re -> re =<< do + C.runContT (W.runWriterT $ W.runWriterT $ R.runReaderT k rq) $ \((as,hs),sta) -> + return{-IO-} $ + Wai.responseStream sta + ( (HTTP.hContentType, Media.renderHeader $ mediaTypeFor reqAccept) + : hs + ) $ \write flush -> + if reqMethod == HTTP.methodHead + then flush + else + let enc = framingEncode (Proxy @framing) (mimeEncode reqAccept) in + let go curr = + case curr of + Left _end -> flush + Right (bsl, next) -> do + unless (BSL.null bsl) $ do + write (BSB.lazyByteString bsl) + flush + enc next >>= go + in enc as >>= go + +-- | Return worse 'HTTP.Status'. +instance Semigroup HTTP.Status where + x <> y = + if rank (HTTP.statusCode x) < rank (HTTP.statusCode y) + then x + else y + where + rank :: Int -> Int + rank 404 = 0 -- Not Found + rank 405 = 1 -- Method Not Allowed + rank 401 = 2 -- Unauthorized + rank 415 = 3 -- Unsupported Media Type + rank 406 = 4 -- Not Acceptable + rank 400 = 5 -- Bad Request + rank _ = 6 +-- | Useful when 'HTTP.Status' is within a 'W.WriterT'. +instance Monoid HTTP.Status where + mempty = HTTP.status200 + mappend = (<>) diff --git a/stack.yaml b/stack.yaml new file mode 100644 --- /dev/null +++ b/stack.yaml @@ -0,0 +1,10 @@ +resolver: lts-12.26 +packages: +- '.' +- location: '../symantic-http' + extra-dep: true +extra-deps: +- http-api-data-0.4@sha256:ad69f7cd0d1e7723abfbed6f88ac987bdf75a402b29de161eb867c6131c9d427 +- monad-classes-0.3.2.2@sha256:793faead28dafb47f115c4dec877ce3e3ffab604f134d852652385632ea0923f +nix: + packages: [zlib] diff --git a/symantic-http-server.cabal b/symantic-http-server.cabal new file mode 100644 --- /dev/null +++ b/symantic-http-server.cabal @@ -0,0 +1,81 @@ +name: symantic-http-server +-- PVP: +-+------- breaking API changes +-- | | +----- non-breaking API additions +-- | | | +--- code changes with no API change +version: 0.0.0.20190324 +category: Protocol +synopsis: symantic-http applied to the derivation of HTTP servers +description: + This library applies + to the building of an HTTP server (request routing and decoding) + based upon , + . + For learning how to use this library, + you can read the demo example + in . +extra-doc-files: +license: GPL-3 +license-file: COPYING +stability: experimental +author: Julien Moutinho +maintainer: Julien Moutinho +bug-reports: Julien Moutinho +-- homepage: + +build-type: Simple +cabal-version: 1.24 +tested-with: GHC==8.4.4 +extra-source-files: + stack.yaml +extra-tmp-files: + +Source-Repository head + location: git://git.autogeree.net/symantic-http + type: git + +Library + exposed-modules: + Symantic.HTTP.Server + default-language: Haskell2010 + default-extensions: + AllowAmbiguousTypes + DataKinds + FlexibleContexts + FlexibleInstances + InstanceSigs + LambdaCase + MultiParamTypeClasses + NamedFieldPuns + NoImplicitPrelude + RecordWildCards + ScopedTypeVariables + TupleSections + TypeApplications + TypeFamilies + TypeOperators + ghc-options: + -Wall + -Wincomplete-uni-patterns + -Wincomplete-record-updates + -fno-warn-tabs + -- -fhide-source-paths + build-depends: + symantic-http >= 0.0 + , base >= 4.10 && < 5 + , base64-bytestring >= 1.0.0.1 + , bytestring >= 0.10 + , containers >= 0.5 + , http-api-data >= 0.4 + , http-media >= 0.7 + , http-types >= 0.12 + , monad-classes >= 0.3.2 + , network-uri >= 2.6 + , stm >= 2.4.5 + , text >= 1.2 + , time >= 1.8 + , transformers >= 0.5 + , wai >= 3.2.1.1 + , warp >= 3.2 + , word8 >= 0.1.3 + -- pkgconfig-depends: zlib + -- extra-libraries: z