Add special characters to Uri, Kotlin - kotlin

Question

So, I have my base URL, which is this:
val GITHUB_BASE_URL: String = "https://api.github.com/search/repositories"
And then I have this code that appends the param q (REPO_NAME_PARAM == query) to the Uri and builds it:
val builtUri: Uri = Uri.parse(GITHUB_BASE_URL).buildUpon()
.appendQueryParameter(REPO_NAME_PARAM, repoName)
.build()
Until here, everything works fine. But, when I try to filter the search of the repositories by the language they are written in (which the URL, for example, should be https://api.github.com/search/repositories?q=hello+language:Kotlin), the + and the : characters get replaced by %2B and %3A. This causes the app to not retrieve the expected results, as the characters got changed in the final url.
This is the code that I currently have
val WRITTEN_IN_PARAM: String = "+language:"
val builtUri: Uri = Uri.parse(GITHUB_BASE_URL).buildUpon()
.appendQueryParameter(REPO_NAME_PARAM, repoName+ WRITTEN_IN_PARAM+"Kotlin")
.build()

Answer 1

2B or not 2B, that is the question. :)
The problem is that the URL parameter is being URL Encoded twice. When we send certain characters in HTTP queries, they need to be encoded. One encoding (considered a shortcut) is to turn a space into a + symbol. The proper way to encode a space is with %20.
However, when the code above gets that already encoded String it doesn't know that the + is already encoded from a space and tries to encode it again (using %2B, the encoding for +).
If you hit the URL you've provided with %20 in place of +, and %3A in place of :, it should work fine. Therefore, the fix is to not send + unless you really want a +, in which case it will be properly encoded to a %2B.
The Fix: The library being used appears to correctly encode strings, just leave the + as a space and it should give you what you need.
Here is a good list of characters and their encoding, if you are interested.