Reading files in a Chrome Extension

Anthony Bruno on March 04, 2018

Often, it is desirable for a Chrome extension to be bundled with files that need to be read. These files may contain data or configuration informat... [Read Full]
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I am new to Chrome Extensions and this is just the info I was looking for. However, I'm having trouble using the chrome.runtime.getUrl function. Whenever I try to use it in a content_script I get:

Uncaught TypeError: chrome.runtime.getUrl is not a function

Do you have an example that shows your complete manifest and script file where this is working?


Hey there!

It looks like you picked up a typo from me. The method is called chrome.runtime.getURL (url is capitalized!). Sorry about that!

If you want to look at an example have a look at my repo: A instance where I getURL is:


This is a neat article, thanks. I've been working with a small Chrome extension recently and it's nice to see other available features.


Hi Anthony, It was a really good and concise article. But I'm left with a small question: If the extension doesn't knows the exact filename (maybe because the files are created by another program with filenames corresponding to timestamps or something like that), it can clearly make it available with the wildcard, but how does it makes the GET? Is there a way for the extension to receive the list of files available in the directory and then make the extension choose a file to send the GET?


Hey Sebastian!

I haven't needed to do this yet, so I did a bit of research. Turns out that this is a rather hard problem! It seems impossible to get it from a content script directly (source). You can potentially chrome.runtime.getManifest() to get the list of web_accessible_resources, but you run into problems if there's wildcard entries.

It may be possible to get the list of possible files with chrome.runtime.getPackageDirectoryEntry(function callback), which is only callable from a background script. I haven't tried it though.


Hi Bruno, I have a question.
I can read file but Can i write this file in Chrome extension?
Thank you and sorry for my English.


Hey DiVoung!

Apologies for my very, very late reply. I only saw this now.

Unfortunately, you cannot write to this file. An alternative may be triggering a file download via this tutorial

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