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Authentication

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PyStream uses two ways of authentication, the username and password to gain access to the server and +a session_token generated by the server to access directories and streaming content.

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Username and Password

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Frontend

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  • UI creates hex values for username and password using native JS

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  • These hex values are then used the calculate the hash

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  • Calculated hash is then base64 encoded using native JS, before sending the signature to the API in an authorization header

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Backend

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  • API decodes the base64 encoded ascii string, then decodes the HEX received in authorization header

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  • Then the value is broken down to, username, signature and timestamp

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  • The decoded username is used to get the stored password from env variables, which are then hex encoded

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  • API creates a hash signature using the hex username, hex password, and the timestamp

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  • These signatures are then compared for authentication purpose

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Session Token

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  • Once the login has been successful, the API creates a randomly generated 64 bit url safe token

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  • This token is stored as unique key for each user

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  • The API then forms a payload with the username, key, and the timestamp

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  • This payload is then encrypted using Cryptography’s Fernet, which can be retrieved only using the key

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  • This encrypted payload is stored as a cookie before sending a JSONResponse with a redirect_url

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Since the UI uses AJAX for authentication POST call, a RedirectResponse from FastAPI will not work, +as the call will simply follow the redirect to GET the content instead of redirecting the page.

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  • The redirect_url from the JSON response is fetched, to alter location.href

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This form of redirect will transfer cookies to the new page but not the headers, +so the username and password are lost in the frontend at this point

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  • From then on, all calls to the backend including redirects, directory navigation and, streaming will carry the cookie

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  • The session_token is the only form of authentication from this point onward

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References

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