Add fetch local file

[zekth]

This fixes #2150

I have 2 questions:
Here : https://github.com/denoland/deno/compare/master...zekth:fetch_local?expand=1#diff-cee0e68f0ac7840274b5171cf4df9dbeR410 i need to handle the content-type but it's in deno_std atm. Any idea? Also, how could i get the content-lenght?

[phil294]

Cool. This repo is like a wish fairy.

I briefly looked into the wikipedia article about file uri scheme and it said that syntax like file://localhost/./myfile.txt is valid too etc.

And what about other protocols like ftp?

Just bringing in ideas.

[zekth]

Cool. This repo is like a wish fairy.

I briefly looked into the wikipedia article about file uri scheme and it said that syntax like file://localhost/./myfile.txt is valid too etc.

And what about other protocols like ftp?

Just bringing in ideas.

FTP may be added in another PR. Concerning all the schemes i'll dig into.

[harrysarson]

Hi, I have a quick question:

As fetch is a asynchronous function, why is a synchronous open file function being used?

[zekth]

Hi, I have a quick question:

As fetch is a asynchronous function, why is a synchronous open file function being used?

Fair point. In fact the open is Synchronous but the reading is still async. Having the open as Sync is like building the header of the http request synchronously (as we do now). It would be interesting to measure the impact of both. BTW, i'll move it to async.

[zekth]

@phil294 about HOST part of the URI it's not used at the moment because we are considering fetching a local file and not getting it throught the network. It can be a possibility but i think the implementation would change a bit. Also i've added a link to the RFC. Maybe a special section of the documentation may be added. For example the RFC is not very clear about the handling of relative path but a lot of interpreters are allowing it. ATM i think it fits the need.

See RFC8089 : https://tools.ietf.org/html/rfc8089

[j-f1]

Is there any metadata associated with this error? If so, would it make sense to JSON-encode it and put it as the body of this response?

[zekth]

As far as i know the errorkind notfound is just an enum for the error code. The only error i think would be not found or permission error. But just put a standard json encoded object like {message:"file not found"} would be interesting. If so someone can give me a hint how to pass it to the Response?

[harrysarson]

Would calling JSON.stringify(e) be a possibility (with try catch)?

[zekth]

I've rebased the PR and added missing types for eslint.
Also for the return of the fetch in case of issue i've added this:
https://github.com/denoland/deno/pull/2152/files#diff-cee0e68f0ac7840274b5171cf4df9dbeR425

@kevinkassimo suggested to use /dev/null for unix and NUL for windows. Is there a way i open those filedescriptors and get the rid of it? any clue about this to land this PR?

[zekth]

If you're satisfied with the using open('NUL') i think we can land it.

[zekth]

So i figured out how to add /dev/null and NUL reading. But the problem is when permission is not allowed we get a Deno.ErrorKind.PermissionDenied the problem is by this way i can't return a HTTP 403 error code of the fetch local.

Is it revelant to add a feature that without the read permission we may be allowed to read NUL and /dev/null ? (in this case it's usefull)

[ry]

I would be very happy to have fetch for local files, but this patch has gone stale. I apologize for not getting it in sooner, @zekth. But in the interest of clearing up old PRs, I'm going to close this.