view tests/test-http-api-httpv2.t @ 37048:fc5e261915b9

wireproto: require POST for all HTTPv2 requests

Wire protocol version 1 transfers argument data via request
headers by default. This has historically caused problems because
servers institute limits on the length of individual HTTP headers
as well as the total size of all request headers. Mercurial servers
can advertise the maximum length of an individual header. But
there's no guarantee any intermediate HTTP agents will accept
headers up to that length.

In the existing wire protocol, server operators typically also
key off the HTTP request method to implement authentication.
For example, GET requests translate to read-only requests and
can be allowed. But read-write commands must use POST and require
authentication. This has typically worked because the only wire
protocol commands that use POST modify the repo (e.g. the
"unbundle" command).

There is an experimental feature to enable clients to transmit
argument data via POST request bodies. This is technically a
better and more robust solution. But we can't enable it by default
because of servers assuming POST means write access.

In version 2 of the wire protocol, the permissions of a request
are encoded in the URL. And with it being a new protocol in a new
URL space, we're not constrained by backwards compatibility
requirements.

This commit adopts the technically superior mechanism of using
HTTP request bodies to send argument data by requiring POST for
all commands. Strictly speaking, it may be possible to send
request bodies on GET requests. But my experience is that not all
HTTP stacks support this. POST pretty much always works. Using POST
for read-only operations does sacrifice some RESTful design
purity. But this API cares about practicality, not about being
in Roy T. Fielding's REST ivory tower.

There's a chance we may relax this restriction in the future. But
for now, I want to see how far we can get with a POST only API.

Differential Revision: https://phab.mercurial-scm.org/D2837

  $ HTTPV2=exp-http-v2-0001

  $ send() {
  >   hg --verbose debugwireproto --peer raw http://$LOCALIP:$HGPORT/
  > }

  $ cat > dummycommands.py << EOF
  > from mercurial import wireprototypes, wireproto
  > @wireproto.wireprotocommand('customreadonly', permission='pull')
  > def customreadonly(repo, proto):
  >     return wireprototypes.bytesresponse(b'customreadonly bytes response')
  > @wireproto.wireprotocommand('customreadwrite', permission='push')
  > def customreadwrite(repo, proto):
  >     return wireprototypes.bytesresponse(b'customreadwrite bytes response')
  > EOF

  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > dummycommands = $TESTTMP/dummycommands.py
  > EOF

  $ hg init server
  $ cat > server/.hg/hgrc << EOF
  > [experimental]
  > web.apiserver = true
  > EOF
  $ hg -R server serve -p $HGPORT -d --pid-file hg.pid
  $ cat hg.pid > $DAEMON_PIDS

HTTP v2 protocol not enabled by default

  $ send << EOF
  > httprequest GET api/$HTTPV2
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     GET /api/exp-http-v2-0001 HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 404 Not Found\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 33\r\n
  s>     \r\n
  s>     API exp-http-v2-0001 not enabled\n

Restart server with support for HTTP v2 API

  $ killdaemons.py
  $ cat > server/.hg/hgrc << EOF
  > [experimental]
  > web.apiserver = true
  > web.api.http-v2 = true
  > EOF

  $ hg -R server serve -p $HGPORT -d --pid-file hg.pid
  $ cat hg.pid > $DAEMON_PIDS

Request to read-only command works out of the box

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/customreadonly
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 200 OK\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 18\r\n
  s>     \r\n
  s>     ro/customreadonly\n

Request to unknown command yields 404

  $ send << EOF
  > httprequest POST api/$HTTPV2/ro/badcommand
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/ro/badcommand HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 404 Not Found\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 42\r\n
  s>     \r\n
  s>     unknown wire protocol command: badcommand\n

GET to read-only command yields a 405

  $ send << EOF
  > httprequest GET api/$HTTPV2/ro/customreadonly
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     GET /api/exp-http-v2-0001/ro/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 405 Method Not Allowed\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Allow: POST\r\n
  s>     Content-Length: 30\r\n
  s>     \r\n
  s>     commands require POST requests

Request to read-write command fails because server is read-only by default

GET to read-write request yields 405

  $ send << EOF
  > httprequest GET api/$HTTPV2/rw/customreadonly
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     GET /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 405 Method Not Allowed\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Allow: POST\r\n
  s>     Content-Length: 30\r\n
  s>     \r\n
  s>     commands require POST requests

Even for unknown commands

  $ send << EOF
  > httprequest GET api/$HTTPV2/rw/badcommand
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     GET /api/exp-http-v2-0001/rw/badcommand HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 405 Method Not Allowed\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Allow: POST\r\n
  s>     Content-Length: 30\r\n
  s>     \r\n
  s>     commands require POST requests

SSL required by default

  $ send << EOF
  > httprequest POST api/$HTTPV2/rw/customreadonly
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 403 ssl required\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Length: 17\r\n
  s>     \r\n
  s>     permission denied

Restart server to allow non-ssl read-write operations

  $ killdaemons.py
  $ cat > server/.hg/hgrc << EOF
  > [experimental]
  > web.apiserver = true
  > web.api.http-v2 = true
  > [web]
  > push_ssl = false
  > allow-push = *
  > EOF

  $ hg -R server serve -p $HGPORT -d --pid-file hg.pid
  $ cat hg.pid > $DAEMON_PIDS

Authorized request for valid read-write command works

  $ send << EOF
  > httprequest POST api/$HTTPV2/rw/customreadonly
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/rw/customreadonly HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 200 OK\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 18\r\n
  s>     \r\n
  s>     rw/customreadonly\n

Authorized request for unknown command is rejected

  $ send << EOF
  > httprequest POST api/$HTTPV2/rw/badcommand
  >     user-agent: test
  > EOF
  using raw connection to peer
  s>     POST /api/exp-http-v2-0001/rw/badcommand HTTP/1.1\r\n
  s>     Accept-Encoding: identity\r\n
  s>     user-agent: test\r\n
  s>     host: $LOCALIP:$HGPORT\r\n (glob)
  s>     \r\n
  s> makefile('rb', None)
  s>     HTTP/1.1 404 Not Found\r\n
  s>     Server: testing stub value\r\n
  s>     Date: $HTTP_DATE$\r\n
  s>     Content-Type: text/plain\r\n
  s>     Content-Length: 42\r\n
  s>     \r\n
  s>     unknown wire protocol command: badcommand\n