hgweb: use parsed request to construct query parameters The way hgweb routes requests is kind of bonkers. If PATH_INFO is set, we take the URL path after the repository. Otherwise, we take the first part of the query string before "&" and the part before ";" in that. We then kinda/sorta treat this as a path and route based on that. This commit ports that code to use the parsed request object. This required a new attribute on the parsed request to indicate whether there is any PATH_INFO. The new code still feels a bit convoluted for my liking. But we'll need to rewrite more of the code before a better solution becomes apparant. This code feels strictly better since we're no longer doing low-level WSGI manipulation during routing. Differential Revision: https://phab.mercurial-scm.org/D2739

hgweb: only recognize wire protocol commands from query string (BC) Previously, we attempted to parse the wire protocol command from `req.form`. Data could have come from the query string or POST form data. The wire protocol states that the command must be declared in the query string. And AFAICT all Mercurial releases from at least 1.0 send the command in the query string. So let's actual require this behavior. This is technically BC. But I'm not sure how anyone in the wild would encounter this. POST has historically been used for sending bundle data. So there's no opportunity to encode arguments there. And the experimental HTTP POST args also takes over the body. So the only way someone would be impacted by this is if they wrote a custom client that both used POST for everything and sent arguments via the HTTP body. I don't believe such a client exists. .. bc:: The HTTP wire protocol server no longer accepts the ``cmd`` argument to control which command to run via HTTP POST bodies. The ``cmd`` argument must be specified on the URL query string. Differential Revision: https://phab.mercurial-scm.org/D2738

hgweb: teach WSGI parser about query strings Currently, req.form uses cgi.parse() to populate form data. Depending on the request, form data can come from POST multipart/form-data, application/x-www-form-urlencoded, or the URL query string. Putting all these things into one data structure makes it difficult to reason about how exactly parameters got to the request. It can lead to wonkiness such as pulling parameters from both the URL and POST data. This commit teaches our WSGI request parser about argument data in query strings. We populate fields containing the query string data and only the query string data so it can't be confused with POST data. Differential Revision: https://phab.mercurial-scm.org/D2737

hgweb: use the parsed application path directly Previously, we assigned a custom system string with a trailing slash to wsgirequest.url. The addition of the trailing slash felt arbitrary and seems to go against how things typically work in WSGI. We also want our URLs to be bytes, not system strings. And, assigning a custom attribute to wsgirequest felt wrong. This commit fixes all those things by removing the trailing slash from the app path, changing consumers to use that variable and to use it without a trailing slash, and removing the custom attribute from wsgirequest. We preserve the trailing slash on {url}. Also, makebreadcrumb strips the trailing slash. So no change to it was needed. Differential Revision: https://phab.mercurial-scm.org/D2736

hgweb: use computed base URL from parsed request Let's not reinvent URL construction in a function that runs the templater. Differential Revision: https://phab.mercurial-scm.org/D2735

hgweb: parse WSGI request into a data structure Currently, our WSGI applications (hgweb_mod and hgwebdir_mod) process the raw WSGI request instance themselves. This means they have to talk in terms of system strings. And they need to know details about what's in the WSGI request. And in the case of hgweb_mod, it is doing some very funky things with URL parsing to impact dispatching. The code is difficult to read and maintain. This commit introduces parsing of the WSGI request into a higher-level and easier-to-reason-about data structure. To prove it works, we hook it up to hgweb_mod and use it for populating the relative URL on the request instance. We hold off on using it in more places because the logic in hgweb_mod is crazy and I don't want to involve those changes with review of the parsing code. The URL construction code has variations that use the HTTP: Host header (the canonical WSGI way of reconstructing the URL) and with the use of SERVER_NAME. We need to differentiate because hgweb is currently using SERVER_NAME for URL construction. Differential Revision: https://phab.mercurial-scm.org/D2734

hgweb: always use "?" when writing session vars This code resolves a string to insert in URLs as part of a query string. Essentially, it resolves the {sessionvars} template keyword, which is used by hgweb templates to build a URL as a string. The whole approach here feels wrong because there's no way of knowing when this code runs how the final URL will look. There could be additional URL fragments added before this template keyword that add a query string component. Furthermore, I don't think there's *any* for req.url to have a query string. That's because the code that populates this variable only takes SCRIPT_NAME and REPO_NAME into account. The "?" character it is searching for would only be added if some code attempted to add QUERY_STRING to the URL. Hacking the code up to raise if "?" is present in the URL yields a clean test suite run. I'm not sure if we broke this code or if it has always been broken. Anyway, this commit removes support for emitting "&" as the first character in {sessionvars} and makes it always emit "?", which is what it was always doing before AFAICT. Differential Revision: https://phab.mercurial-scm.org/D2733

hgweb: rename req to wsgireq We will soon introduce a parsed WSGI request object so we don't have to concern ourselves with low-level WSGI matters. Prepare for multiple request objects by renaming the existing one so it is clear it deals with WSGI. We also remove a symbol import to avoid even more naming confusion. # no-check-commit because of some new foo_bar naming that's required Differential Revision: https://phab.mercurial-scm.org/D2732

hgweb: validate WSGI environment dict The wsgiref.validate module contains useful functions for validating that various WSGI data structures are proper. This commit adds validation of the environment dict to our built-in HTTP server, which turns an HTTP request into an environment dict. The check discovered that we weren't always setting QUERY_STRING, which would cause the cgi module to fall back to sys.argv. So we change things to always set QUERY_STRING. The check passes on Python 2 and 3. Differential Revision: https://phab.mercurial-scm.org/D2731

hgweb: ensure all wsgi environment values are str Previously, we had a few entries that were bytes on Python 3. PEP-0333 states that all entries must be the native str type (bytes on Python 2, str on Python 3). This required a number of changes to hgweb_mod to unbreak things on Python 3. I suspect there still may be some regressions. I'm going to introduce a data structure that represents a parsed WSGI request in upcoming commits. This will hold bytes and will allow us to stop using raw literals throughout the WSGI code. Differential Revision: https://phab.mercurial-scm.org/D2730