Opened 5 months ago

Last modified 5 months ago

#7296 closed change

Implement lightweight URL parsing — at Version 16

Reported by: mjethani Assignee: mjethani
Priority: P2 Milestone:
Module: Core Keywords:
Cc: greiner Blocked By:
Blocking: #7000 Platform: Unknown / Cross platform
Ready: yes Confidential: no
Tester: Unknown Verified working: no
Review URL(s):

https://codereview.adblockplus.org/30013574/

Description (last modified by mjethani)

Background

In the extension we use the URL object just to extract the protocol and the hostname from a URL. This is not very efficient as it must "canonicalize" (normalize) and then parse the entire URL. Extraction of the protocol and the hostname can be implemented using a regular expression instead:

let [, protocol, hostname] = /^([^:]+:)(?:\/\/(?:[^/]*@)?(\[[^\]]*\]|[^:/]+))?/
                             .exec(url);

Note: This would work only for URLs that are already canonicalized (i.e. http:example.com:80?foo has been converted to http://example.com/?foo), such as those received by the onBeforeRequest handler in the extension.

What to change

Implement a function parseURL() that uses the above regular expression to extract the protocol and the hostname from a URL. It should return an object containing the properties href, protocol, and hostname and a toString() method that returns the value of the href property.

For any url that is a canonicalized URL, all of the following should be true:

  • parseURL(url).href === new URL(url).href
  • parseURL(url).protocol === new URL(url).protocol
  • parseURL(url).hostname === new URL(url).hostname
  • parseURL(url).toString() === new URL(url).toString()

For the tests, pick up some ideas from Chromium. Note however that parseURL() should expect an already canonicalized URL; accordingly, the tests should use only canonicalized URLs.

Change History (16)

comment:1 Changed 5 months ago by mjethani

  • Blocking 7000 added

comment:2 Changed 5 months ago by mjethani

  • Description modified (diff)

comment:3 Changed 5 months ago by mjethani

  • Description modified (diff)

comment:4 Changed 5 months ago by mjethani

  • Description modified (diff)

comment:5 Changed 5 months ago by greiner

  • Cc greiner added

Are we expecting any issues with IDNs, FQDNs or differently encoded (i.e. punycode or URL-encoding) URLs here? What about URLs that contain username and password or a port?

While I tried the regex and it seems to be able to handle any of those cases, we should probably make sure that our tests cover all possible cases that are allowed by the URL standard.

comment:6 Changed 5 months ago by mjethani

For the regular expression in the description (which may not be exactly what we end up using), I went for the easy route: I looked at the implementation of URL parsing in Chromium (which is apparently based on Mozilla). I may have got it wrong of course. The best way to ensure that it works as intended is to write tests that compare against the output from the native URL object.

comment:7 Changed 5 months ago by mjethani

Regarding Punycode, we dropped the assumption in Core that URLs will be anything but properly encoded (#6647) (which means the hostname part is expected to be Punycode).

comment:8 Changed 5 months ago by mjethani

  • Description modified (diff)
  • Summary changed from Implement hostname extraction using a regular expression to Implement lightweight URL parsing

comment:9 Changed 5 months ago by mjethani

  • Review URL(s) modified (diff)

comment:10 Changed 5 months ago by mjethani

I have an implementation now. I need to polish it up and add some more tests.

comment:11 Changed 5 months ago by mjethani

  • Owner set to mjethani

comment:12 Changed 5 months ago by mjethani

  • Description modified (diff)

comment:13 Changed 5 months ago by mjethani

  • Description modified (diff)

comment:14 Changed 5 months ago by mjethani

  • Description modified (diff)
  • Priority changed from Unknown to P2
  • Ready set

comment:15 Changed 5 months ago by mjethani

  • Status changed from new to reviewing

comment:16 Changed 5 months ago by mjethani

  • Description modified (diff)
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