Azure File Storage urls don't work the first time

user_1073742 0
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Background: I am moving a legacy app that was storing images and documents on local disk on the web server, over toward a PaaS Azure web app and using Azure File Storage to store and serve the files.

Question:

I have noticed that sometimes the url for file download fails the first time, either image links on a page are broken until I refresh or a download fails the first time, then succeeds the next. I am guessing that this is due to some issue with how Azure File Storage works and it hasn't started up or something. The only consistent thread I have observed is that this seems to happen once or twice in the morning when I am first working with it. I am guessing maybe my account has to ramp up or something, so its not ready on the first go round. I tried to come up with steps to reproduce, but I could not reproduce the symptom. If my hunch is correct, I will have to wait until tomorrow morning to try. I will post more detailed error information if/when I can.

    var fullRelativePath = $"{_fileShareName}/{_fileRoot}/{relativePath}".Replace("//","/");
    return $"{_fileStorageRootUrl}{fullRelativePath}{_fileStorageSharedAccessKey}";

Thanks!

azure-storage-files azure-storage azure
1 Answers

So its been a while but I remember I was able to resolve this, so I'll be writing this from memory. To be able to access an image from file storage via a URL, you need to use a SAS token. I already had, which is why I was perplexed about this. I'm not sure if this is the ideal solution, but what I wound up doing was just appending some random characters to the end of the url, after the SAS token, and that make it work. My guess is this somehow made it unique, which may have helped it bypass some caching mechanism that was behaving erratically.

I'll see if I can dig up working example from my archive. If so, I'll append it to this answer.

user_10737420
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