What is required for using HTTP POST in Canvas app communication?

When using HTTP POST in Canvas app communication, the requirement that the Session ID is not exposed is crucial for maintaining security and integrity of data exchange between the Canvas app and the server. This design choice helps to prevent sessions from being hijacked through URL manipulation, as POST requests typically send data in the body of the request instead of appending it to the URL as query parameters.

In this context, Canvas apps are designed with security measures in mind, and not exposing the Session ID ensures that sensitive user session information is safeguarded during communication. This practice enhances overall security by mitigating exposure to potential attacks that could exploit session identifiers.

Additionally, using POST requests allows for the transmission of larger amounts of data, which is often necessary for interactions that involve creating or updating resources on the server while maintaining a secure environment by not revealing the Session ID in the request URL.