http2: add altsvc support #17917

jasnell · 2017-12-29T17:56:11Z

Add support for sending and receiving ALTSVC frames.

As defined by https://tools.ietf.org/html/rfc7838

ping @nodejs/http2

Checklist

make -j4 test (UNIX), or vcbuild test (Windows) passes
tests and/or benchmarks are included
documentation is changed or added
commit message follows commit guidelines

Affected core subsystem(s)

http2

addaleax

LGTM

I would be open to spelling out the name in the API as alternateService or similar

TimothyGu · 2017-12-29T22:55:05Z

src/node_http2.cc

+    Integer::New(isolate, id),
+    String::NewFromOneByte(isolate,
+                           altsvc->origin,
+                           v8::NewStringType::kInternalized,


Any reason ehy this is internalized?

nah, cut'n'paste error actually

TimothyGu · 2017-12-29T22:57:21Z

lib/internal/http2/core.js

+      throw new errors.RangeError('ERR_OUT_OF_RANGE', 'stream');
+
+    if (origin)
+      origin = (new URL(origin)).origin;


I think it would be helpful to make sure the URL’s scheme is HTTP or HTTPS (or at least the origin is not ’null’.

There is a check for a falsy origin on line 1195.

A “null origin” is not that the returned origin is null but that it is 'null'. Try new URL('abc:').origin, which IMO should be forbidden.

ah, right, forgot about that little nuance. Sigh.

Ok, added a check for 'null' in the code and in the test

TimothyGu · 2017-12-29T23:03:57Z

src/node_http2.cc

+  int32_t id = args[0]->Int32Value(env->context()).ToChecked();
+
+  // TODO(jasnell): This is not exactly right as these are supposed to
+  // be ASCII only.


Is this TODO not currently solvable? We know for a fact that at least the origin is ASCII-only.

Yep, was already working on it :-)

TimothyGu · 2017-12-29T23:15:47Z

doc/api/http2.md

+* `stream` {number} The numeric identifier of a stream (or `0`). Defaults to
+  `0`.
+
+Submits an `ALTSVC` frame (as defined by [RFC 7838][]) to the connected client.


Would help if what stream ID 0 (and why it must have an origin) could be explained. Not everyone likes to read RFC’s.

jasnell · 2017-12-30T07:47:40Z

@addaleax ... renamed the public API function as suggested.

TimothyGu

Mostly nits. Thanks for doing this.

TimothyGu · 2017-12-30T11:39:14Z

lib/internal/http2/core.js

+    if (len > 16382)  // Max length permitted for ALTSVC
+      throw new errors.TypeError('ERR_HTTP2_ALTSVC_LENGTH');
+
+    if (stream === 0 && !origin || origin.length === 0 || origin === 'null')


Maybe the !origin could be written out explicitly as origin !== undefined? (Ditto below.)

And also I think the origin.length check or 'null' check fail it should use a more informative error code.

There is also the issue of if we want to error out on invalid origin when stream is non-zero. I think we should, for the same reason as we are erroring out on non-string type regardless of what stream is. So overall I think the logic should look like

// type checks first if (origin !== undefined && typeof origin !== 'string') error(); if (origin === undefined) { if (stream === 0) error(); } else { // we shouldn’t make exceptions for empty origin string either: either it’s undefined or it has to be a valid URL. origin = new URL(origin).origin; if (origin === 'null') error(); if (stream !== 0) error(); }

If we simplify the signature to allow the second argument to be either a string or a number, then we don't necessarily have to jump through this hoop. Will stew on it a bit more

TimothyGu · 2017-12-30T11:59:06Z

doc/api/http2.md

+Sending an `ALTSVC` frame with stream ID `0` (the default) indicates that
+the alternate service is associated with the given `origin`. Sending an
+`ALTSVC` frame with a specific stream ID indicates that the alternate
+service is associated with the origin of the given `Http2Stream`.


Hmm, would it be a good idea to make the second parameter number|string, where when it’s number it has to be a valid stream ID and when it’s a string it would be used as the origin (and thus the stream ID is implicitly 0)? That’s only a good idea if we are certain they won’t make it possible to have a stream ID and origin at the same time, but does have the advantage of hiding the 0 as an implementation detail (it’s sort of a magic number otherwise).

Thanks for writing the documentation though: it’s very helpful.

I've been stewing over it. I'm starting to have a real dislike for polymorphic function signatures but it would make things a bit easier in both the implementation and on the user.

TimothyGu · 2017-12-30T12:01:55Z

doc/api/http2.md

 ### Class: ClientHttp2Session
 <!-- YAML
 added: v8.4.0
 -->

+#### Event: 'altsvc'


I sort of feel this name should correspond with the name of the method on the server side. I’m ambivalent about whether alternateService is a better name than altsvc though: I feel eventually most people would refer to it as ALTSVC (HTTP/2 frame) or Alt-Svc (HTTP/1.1 header), while technically the name of the header is alternateServices.

@addaleax ... given that you were the one that made the original rename suggestion, what do you think here?

@jasnell If everybody here agrees that it’s going to be referred to as ALTSVC anyway, yea, probably best to stick with it?

Either way, yes, +1 for being consistent :)

I think altsvc is definitely going to be the most common given the way the header and frame type are defined. I'll switch the API call back :-)

TimothyGu · 2017-12-30T12:06:34Z

src/node_http2.cc

+
+  int32_t id = args[0]->Int32Value(env->context()).ToChecked();
+
+  // origin and value are both required to be ASCII, handle them as such.


Is this requirement enforced for the value string? If not then we should, to combat the HTTP header encoding debacle that only recently got rectified. In fact IMO we should verify that it only consists of HTTP tokens, similar to the HTTP header checks.

Origin is fine because it’s guaranteed to be ASCII by the URL parser.

The value is not limited to token. It will contain a sequence of uri-host constructs (host:port) within quoted strings. At the C++ level, we write these out as one-byte strings so there is at least some level of enforcement there. And on the receiving side, these are treated as one byte strings so the value will be received correctly. Anyone using extended characters will just see those get corrupted. Because of the performance implications and the fact that this is a non-critical API, I don't think we need to validate every character.... although, it would be good to extend the documentation on this a bit more -- as you said, not everyone likes to read RFCs :-)

The additional documentation is always a plus.

Anyone using extended characters will just see those get corrupted.

Well that’s certainly not the best of outcomes. If this is truly a non-critical API, I think we should ensure correctness above performance. Good call on quotation marks though, and in that case I think simply using a /[\x00-\x7f]/ check should be enough.

There may also be some security implications involved, when '\uff20' is treated identically to `'\u0020' by the V8 API.

Ok, added a check

jasnell · 2017-12-30T19:20:21Z

@TimothyGu @addaleax ... updated! Went with the two argument signature and reworked the error codes a bit. Also extended the documentation to be more useful. PTAL

jasnell · 2018-01-01T18:10:18Z

CI: https://ci.nodejs.org/job/node-test-pull-request/12359/

TimothyGu · 2018-01-01T00:03:40Z

lib/internal/http2/core.js

@@ -32,6 +32,8 @@ const kMaxFrameSize = (2 ** 24) - 1;
 const kMaxInt = (2 ** 32) - 1;
 const kMaxStreams = (2 ** 31) - 1;

+const kQuotedString = /^[\x09\x32\x21-\x5b\x5d-\x7e\x80-\xff]*$/;


Is the x32 meant to be x20?

Also, x80-xff can’t really happen because the specific quoted-string is specified to contain (optionally) a url-host, a colon, and a port number, all of which is in the ASCII range. Removing support for that will make this regex not generic for quoted-string but I think it’s a good change.

oh ha!! thinking hex, typed decimal. sigh

I'd still prefer to keep the x80-xff range given the definition of quoted-string. Yes, it shouldn't happen, but the spec definition technically allows for it. It will be up to the user to validate that what they get is a valid value.

Okay. I can’t agree with that interpretation of the spec but this is not a blocker for me like the corruption issue was.

TimothyGu · 2018-01-01T00:06:53Z

doc/api/http2.md

+
+The format of the `alt` parameter is strictly defined by [RFC 7838][] as an
+ASCII string containing a comma-delimited list of "alternative" protocols
+associated with a specific host and port.


Maybe this could mention the clear special value as well.

Yeah, good idea

TimothyGu

LGTM.

TimothyGu · 2018-01-02T03:14:18Z

lib/internal/http2/core.js

+
+    if (typeof originOrStream === 'string') {
+      origin = (new URL(originOrStream)).origin;
+      if (origin.length === 0 || origin === 'null')


The length check is unnecessary: serialized origins cannot be empty.

mcollina · 2018-01-02T08:20:55Z

doc/api/http2.md

+* `alt` {string} A description of the alternative service configuration as
+  defined by [RFC 7838][].
+* `originOrStream` {string|number} Either a URL string specifying the origin or
+  the numeric identifier of an active `Http2Stream`.


it is not clear where this number can be found.

mcollina · 2018-01-02T08:30:45Z

lib/internal/http2/core.js

+    let origin;
+
+    if (typeof originOrStream === 'string') {
+      origin = (new URL(originOrStream)).origin;


I think we would be better of in accepting a URL object rather than a string, or an object with an origin property. The typical usage is to send this down for every session, and passing an object allows a user to avoid parsing a URL for every request.

Let's support both. If originOrStream is passed in as an object with an origin property, it will be used. This risks, of course, the value not being strictly ASCII, but we can document that requirement.

Add support for sending and receiving ALTSVC frames.

jasnell · 2018-01-02T17:43:44Z

@mcollina ... updated to support passing in URL objects and objects-with-origin. Updated docs and test. PTAL

jasnell · 2018-01-02T23:03:06Z

CI: https://ci.nodejs.org/job/node-test-pull-request/12379/

jasnell · 2018-01-03T00:07:57Z

CI is good. One failure on freebsd is unrelated.

jasnell · 2018-01-03T05:20:46Z

@mcollina ... I plan to get this landed in the morning. Can you take one final look?

mcollina

LGTM

Add support for sending and receiving ALTSVC frames. PR-URL: #17917 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

jasnell · 2018-01-03T16:53:25Z

Landed in ce22d6f

Add support for sending and receiving ALTSVC frames. PR-URL: nodejs#17917 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

Add support for sending and receiving ALTSVC frames. Backport-PR-URL: #18050 PR-URL: #17917 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

Notable change: * async_hooks: - deprecate AsyncHooks Sensitive API and runInAsyncIdScope. Neither API were documented. (Andreas Madsen) #16972 * deps: - update nghttp2 to 1.29.0 (James M Snell) #17908 - upgrade npm to 5.6.0 (Kat Marchán) #17535 - cherry-pick 50f7455 from upstream V8 (Michaël Zasso) #16591 * events: - remove reaches into _events internals (Anatoli Papirovski) #17440 * http: - add rawPacket in err of `clientError` event (XadillaX) #17672 * http2: - implement maxSessionMemory (James M Snell) #17967 - add initial support for originSet (James M Snell) #17935 - add altsvc support (James M Snell) #17917 - perf_hooks integration (James M Snell) #17906 * net: - remove Socket.prototype.write (Anna Henningsen) #17644 - remove Socket.prototype.listen (Ruben Bridgewater) #13735 * repl: - show lexically scoped vars in tab completion (Michaël Zasso) #16591 * stream: - rm {writeable/readable}State.length (Calvin Metcalf) #12857 - add flow and buffer properties to streams (Calvin Metcalf) #12855 * util: - allow wildcards in NODE_DEBUG variable (Tyler) #17609 * zlib: - add ArrayBuffer support (Jem Bezooyen) #16042 * Addedew collaborator** - [starkwang](https://github.com/starkwang) Weijia Wang * Addedew TSC member** - [danbev](https://github.com/danbev) Daniel Bevenius PR-URL: #18069

Add support for sending and receiving ALTSVC frames. Backport-PR-URL: #18050 PR-URL: #17917 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

Notable change: * async_hooks: - deprecate AsyncHooks Sensitive API and runInAsyncIdScope. Neither API were documented. (Andreas Madsen) #16972 * deps: - update nghttp2 to 1.29.0 (James M Snell) #17908 - upgrade npm to 5.6.0 (Kat Marchán) #17535 - cherry-pick 50f7455 from upstream V8 (Michaël Zasso) #16591 * events: - remove reaches into _events internals (Anatoli Papirovski) #17440 * http: - add rawPacket in err of `clientError` event (XadillaX) #17672 * http2: - implement maxSessionMemory (James M Snell) #17967 - add initial support for originSet (James M Snell) #17935 - add altsvc support (James M Snell) #17917 - perf_hooks integration (James M Snell) #17906 - Refactoring and cleanup of Http2Session and Http2Stream destroy (James M Snell) #17406 * net: - remove Socket.prototype.write (Anna Henningsen) #17644 - remove Socket.prototype.listen (Ruben Bridgewater) #13735 * repl: - show lexically scoped vars in tab completion (Michaël Zasso) #16591 * stream: - rm {writeable/readable}State.length (Calvin Metcalf) #12857 - add flow and buffer properties to streams (Calvin Metcalf) #12855 * util: - allow wildcards in NODE_DEBUG variable (Tyler) #17609 * zlib: - add ArrayBuffer support (Jem Bezooyen) #16042 * Addedew collaborator** - [starkwang](https://github.com/starkwang) Weijia Wang * Addedew TSC member** - [danbev](https://github.com/danbev) Daniel Bevenius PR-URL: #18069

This commit also includes prerequisite error definitions from c75f87c and 1698c8e. Add support for sending and receiving ALTSVC frames. Backport-PR-URL: nodejs#18050 PR-URL: nodejs#17917 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

This commit also includes prerequisite error definitions from c75f87c and 1698c8e. Add support for sending and receiving ALTSVC frames. Backport-PR-URL: #18050 Backport-PR-URL: #20456 PR-URL: #17917 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Tiancheng "Timothy" Gu <[email protected]> Reviewed-By: Matteo Collina <[email protected]>

nodejs-github-bot added the lib / src Issues and PRs related to general changes in the lib or src directory. label Dec 29, 2017

addaleax approved these changes Dec 29, 2017

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jasnell force-pushed the http2-altsvc branch from d5afa4f to 89b4130 Compare December 30, 2017 19:19

jasnell mentioned this pull request Dec 30, 2017

[Tracking Issue]: Some http2 todos #17746

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jasnell force-pushed the http2-altsvc branch from 5692025 to 852a67f Compare January 1, 2018 19:50

jasnell added the http2 Issues or PRs related to the http2 subsystem. label Jan 2, 2018

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http2: add altsvc support

df50686

Add support for sending and receiving ALTSVC frames.

jasnell force-pushed the http2-altsvc branch from 852a67f to df50686 Compare January 2, 2018 17:01

[Squash] Support URL and objects-with-origin

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jasnell closed this Jan 3, 2018

MylesBorins mentioned this pull request Jan 10, 2018

v9.4.0 proposal #18069

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MylesBorins added the dont-land-on-v6.x label Jan 19, 2018

MylesBorins mentioned this pull request May 2, 2018

v8.11.2 proposal #20478

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		int32_t id = args[0]->Int32Value(env->context()).ToChecked();

		// origin and value are both required to be ASCII, handle them as such.

http2: add altsvc support #17917

http2: add altsvc support #17917

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jasnell commented Dec 29, 2017

Checklist

Affected core subsystem(s)

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jasnell commented Jan 2, 2018

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