[PATCH 1 of 4 V2] debug: add a 'debugdownload' command

[Yuya Nishihara]

On Mon, 08 Jan 2018 12:00:18 +0100, Boris Feld wrote:
> # HG changeset patch
> # User Boris Feld <boris.feld at octobus.net>
> # Date 1513326616 -3600
> #      Fri Dec 15 09:30:16 2017 +0100
> # Node ID cfcfc7938b0411f91f8626500cafaad0d522e1ee
> # Parent  f04d16bef2c71986f256a7bf2c97163d726d4909
> # EXP-Topic largefile-url
> # Available At https://bitbucket.org/octobus/mercurial-devel/
> #              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r cfcfc7938b04
> debug: add a 'debugdownload' command
> 
> This command resolve and fetch and URL through the Mercurial logic. Mercurial
> logic add various headers (including authentication) while resolving an URL so
> the commands helps with building the same request Mercurial would be doing.
> 
> A new test file is created because we'll add more logic regarding Mercurial
> download logic and it will grow to a reasonable size.
> 
> diff --git a/mercurial/debugcommands.py b/mercurial/debugcommands.py
> --- a/mercurial/debugcommands.py
> +++ b/mercurial/debugcommands.py
> @@ -69,6 +69,7 @@ from . import (
>      templater,
>      treediscovery,
>      upgrade,
> +    url as urlmod,
>      util,
>      vfs as vfsmod,
>  )
> @@ -786,6 +787,28 @@ def debugdiscovery(ui, repo, remoteurl="
>      localrevs = opts['rev']
>      doit(localrevs, remoterevs)
>  
> +

Please run test-check-commit.t.

> +_chunksize = 4 << 10
> +
> + at command('debugdownload',
> +    [
> +        ('o', 'output', '', _('URL')),

Nit: s/URL/output file/ ?

> +def debugdownload(ui, url, output=None, **opts):
> +    """Download a resource using Mercurial logic and config
> +    """
> +    fh = urlmod.open(ui, url, output)
> +
> +    dest = ui
> +    if output:
> +        dest = open(output, "wb", _chunksize)
> +
> +    data = fh.read(_chunksize)
> +    while data:
> +        dest.write(data)
> +        data = fh.read(_chunksize)

Need to close dest if it isn't ui. Perhaps we can extract a subset of
cmdutil.makefileobj() which requires a repo object. (We could make a repo
argument optional, but that would conflict with my patches to port it to
templater. :)