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Shared Access Signature and URL encoding on Windows Azure

Playing a little with Shared Access Signature was quite nice. In this moment this new functionality has a great potential. Playing a little with it I found an odd bug that I introduce from the code. From the start you need to know that this bug was generated by me and the cause of it was not Windows Azure.
Normally after we generate the access signature we are adding it to the URL that we want to access and we get a code similar to this:
var accessSignature = myTable.GetSharedAccessSignature(…);
string accessURL = tableAccessURL + … + accessSignature;
Uri accessUri = new Uri(accessURL);
string myAccessLink = accessUri.ToString();
The only problem here is that the accessSignature can contains specials characters like ‘=’ or ‘+’. This kind of characters needs to be encoded in the URL. Because of this from time to time we will get an URL that is not valid. In my case last time I got an access signature that contained this kind of specials characters for 4 times in a row. Because of this we cannot accept this kind of solutions.
A better way to get the string of an Uri object is to use AbsoluteUri for example. Or any other method that know to encode the URL characters. Using this method we will not need to worry about encoding problems. The code should look like this:
var accessSignature = myTable.GetSharedAccessSignature(…);
string accessURL = tableAccessURL + … + accessSignature;
Uri accessUri = new Uri(accessURL);
string myAccessLink = accessUri.AbsoluteUri();
Another solution for our problem is to use “EscapeUriString” method of the uri. This will do the same think for us.
In conclusion we should be carefully about how we convert any kind of Uri to a string and know very well what kind of characters can appear in it. If the URL that is generated doesn’t need to be read by a user I will also try to escape the uri string using any solutions that is available.


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