"pub serve" should provide the ability to look up mappings between source and output lines

[DartBot]

<img src="https://avatars.githubusercontent.com/u/188?v=3" align="left" width="96" height="96"hspace="10"> Issue by nex3
Originally opened as dart-lang/sdk#16061

---

It should be possible (via the "pub serve" websocket API) to provide the server with a source file and line number and get the corresponding output URL and line number, and vice versa.

This particular bug is intended to track the bare minimum feature set necessary to provide parity with the editor's current server. Specifically, it only needs to support Dart inputs and outputs with no transformers in between. Issue dart-archive/barback#6 is tracking the broader use of this with all transformers.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/188?v=3" align="left" width="48" height="48"hspace="10"> Comment by nex3

---

Marked this as blocking dart-lang/sdk#15830.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

---

Removed Priority-Unassigned label.
Added Priority-Medium label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

---

Set owner to @munificent.
Removed Type-Defect label.
Added Type-Enhancement, Started labels.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

---

Hey, Keerti and/or Devon!

Can you sketch out what kind of Web Socket API you'd like to see for this?

Do you want a mapping from source file to served URL, or vice versa? Both? Do you need column information or just lines?

---

cc @keertip.
cc @devoncarew.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

---

Added NeedsInfo label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

---

Talked about it with Keerti this morning. My understanding is that the Editor needs mapping in both directions:

1. Given a package name, a relative path to a source file on disc within that package, and a line number, return the URL to the corresponding output for that file as is served by pub serve along with the matching line number in the output file.
2. Given a URL for an output asset and a line number, return the package name, relative path and line number for the source file that corresponds to that asset.

Ex. package "foo", path: "some/path.dart" <-> "/packages/foo/some/path.dart"

We're OK with only supporting .dart files that are not transformed (or at least not transformed in a way that affects line numbering) for a first-pass implementation of this.

Keerti, does that sound right? Do you need column information too, or just lines?

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

---

Added Started label.

[DartBot]

<img src="https://avatars.githubusercontent.com/u/46275?v=3" align="left" width="48" height="48"hspace="10"> Comment by munificent

---

Added Fixed label.