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The network request logger

harshanvn edited this page Mar 4, 2015 · 45 revisions

µBlock comes with a network request logger, which gives the ability to inspect network requests, whether they were blocked or allowed, and which filter, if any, matched a network request.

To access the network request logger, click on the eye icon of µBlock's popup UI:

Figure 1

The request logger will open in a new tab:

Figure 2

Take note that the network request logger in µBlock is a forward-looking logger: this means only future requests can be logged. In the spirit of efficiency, µBlock will log network requests for a tab if and only if there is a logger opened for that tab.


Components

Figure 2

The drop-down selector is to choose for which tab network requests should be logged. Each network request logger can log only one tab at a time, in order to identify clearly all the network requests which originate from a specific web page.

You may have multiple network request loggers open at the same time though -- there is no limit.

The big refresh button aside the tab selector is to refresh the content of the selector. When tabs are added or closed, you need to refresh explicitly the selector so that its content reflects the current tabs.

Note in the figure above the entry named "Behind the scene": selecting this entry allows you to see behind-the-scene network requests, i.e. those network requests which do not originate from a specific tab. More about this here.


Figure 3

This is to force a refresh of the tab which is currently being observed.


Figure 4

This is to remove all the logged entries.


Figure 6

This is to filter the entries to display. The entries which are remove from view are not removed from the logger, they are just hidden according to the filter expression.

Some details about how to filter logged entries:

If the first character is:

  • -: display only blocked requests
  • +: display only allowed-through-exception-filter requests
  • !: negate the rest of the expression

A matching filtering expression is one which matches from left-to-right the text in an entry. Examples of filtering expression:

  • - script: show all blocked requests of type script
  • + xhr: show all force-allowed requests of type xhr
  • !image: show entries which do not contain the string "image"
  • script google: show all requests containing the strings "script" then "google"

The filter expression can be a plain regular expression:

  • /image|css/: show all requests which type is image or css
  • !/image|css/: show all requests which type is not image neither css

Figure 5

This is the maximum number of entries allowed in the request logger. When the maximum is reached, the oldest entries at the bottom will be removed to make place to newest entries at the top.

This is useful to be sure the request logger does not unduly consume a huge amount of memory if left open for long period of time. Usually, the most recent entries are the ones of interest. When this value is not set, there is a built-in limit of 25,000 entries.

One could leave the logger opened for long period of time with the "Behind the scene" selected to find out what the browser and other installed extensions are doing behind the scene.

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