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CS 162 HW 3

GET request

Table of contents

  1. Files
  2. Directories

Files

Implement handle_files_request to handle HTTP GET requests for files. You will need to call serve_file accordingly. You should also be able to handle requests to files in subdirectories of the files directory (e.g. GET /images/hero.jpg).

  • If the file denoted by path exists, call serve_file on it. Read the contents of the file and write it to the client socket.
    • Make sure you set the correct Content-Length HTTP header. The value of this header should be the size of the HTTP response body, measured in bytes. For example, Content-Length: 7810. You can use snprintf to convert an integer into a string.
    • You must use the read and write syscalls for this assignment. Any implementations using fread or fwrite will not earn any credit. This is purely for pedagogical reasons; we want you to be comfortable with the fact that low-level I/O may or may not perform the entire operation on all the bytes requested.
  • Else, serve a 404 Not Found response (the HTTP body is optional) to the client. There are many things that can go wrong during an HTTP request, but we only expect you to support the 404 Not Found error message for a non-existent file. After finishing this part, curling for index.html should output the contents of the file index.html.

Directories

Implement handle_files_request to handle HTTP GET requests for both files and directories.

  • You will now need to determine if path in handle_files_request refers to a file or a directory. The stat syscall and the S_ISDIR or S_ISREG macros will be useful for this purpose. After finding out if path is a file or a directory, you will need to call serve_file or serve_directory accordingly.

  • If the directory contains an index.html file, respond with a 200 OK and the full contents of the index.html file. You may not assume that directory requests will have a trailing slash in the query string.
    • The http_format_index function in libhttp.c may be useful.
  • If the directory does not contain an index.html file, respond with an HTML page containing links to all of the immediate children of the directory (similar to ls -1), as well as a link to the parent directory.
    • The http_format_href function in libhttp.c may be useful.
    • To list the contents of a directory, good functions to use are opendir and readdir.

  • If the directory does not exist, serve a 404 Not Found response to the client.

  • You don’t need to worry about extra slashes in your links (e.g. //files///a.jpg is perfectly fine). Both the file system and your web browser are tolerant of it.

  • You do not need to handle file system objects other than files and directories (i.e. you do not need to handle symbolic links, pipes, or special files).

  • Remember to close the client socket before returning from the handle_files_request function.

  • Make helper functions to reuse similar code when you can. It will make your code easier to debug!

After finishing this part, curling for the root directory / should output the contents of the file index.html. All tests for Basic Server tests should pass on the autograder.