The primary objective of this assignment was to develop a HTTP client to interact with a HTTP server that maintains a database of books. This involved handling various HTTP requests and managing stateless connections.
The core logic of the client and its API is implemented in the client.c file. Here are some key components:
- Buffer Management: A buffer is maintained for the message data, and two pointers initially set to
NULLmanage the values for the session's cookie and token. - TCP Connections: Each command execution within the
whileloop initiates a new TCP connection to uphold the stateless nature of HTTP, ensuring that the outcome of the current request is independent of any previous ones.
Utility functions are consolidated in the functions.c file, forming the solution's backbone. Each command function, such as register, login, and logout, corresponds to specific HTTP request types: GET, POST, and DELETE.
- HTTP Headers: These are constructed using helper functions provided in
requests.c, developed during a laboratory session. - JSON Handling: Commands with data payloads utilize JSON objects, built using the Parson library for compatibility with the procedural programming style of C.
- Response Parsing: Server responses are parsed into strings. Functions like
strtok()andstrchr()are used extensively to extract tokens or cookies, necessary due to the limitations of the C programming language.
Given the project's adherence to procedural programming in C, the Parson library was chosen for JSON manipulation due to its simplicity and robust functionality.
- Procedural Compatibility: Perfect fit for a project not using object-oriented programming.
- Intuitive API: Allows for straightforward creation and parsing of JSON objects with minimal code.
- Open Source and Reliable: Parson is well-documented, open-source, and considered bug-free, making it ideal for educational and developmental use.