Assignment: Construct an HTTP server and add functionality to allow it to implement a simple web framework. It should:

• serve named files in the top level directory or in named subdirectories
• return a 404 error when appropriate
• try interpreting name.html as a zero-argument function name(), calling name() and returning its output
• try interpreting name/arg or name/arg1/arg2... as a function name() with some number of arguments, calling name on those arguments and returning its output.

1. Clone the repository, enter directory web_framework, and run the HTTP server as

   python server.py 1234
   

where 1234 is a port to listen on. Point your browser to http://localhost:1234 to view the content being served. If no port is found on the command line, the default is 1924. Bear in mind that some ports may require special permissions. Port 0 is forbidden in this implementation.

1. This program requires Python3.

2. There is a requirements file, but at present (20140526) it only loads Ipython, which is not necessary to run the server.

3. The server will serve named HTML files found in the files directory, including those in nested subdirectories. See the section Results tested for, below, for examples.

4. Functions corresponding to URLs should be added to functions.py in the section marked with a row of hash-signs. The server will keep track of those functions — assuming they work as written — without having to be restarted. When one of them occurs as the rightmost part of the path in a URL it will be called as a function; its return value will be saved to a file which is then served to the user. For instance, if the user sends a GET request

   http://localhost:1234/time.html

the function functions.Functions.time() will be run; it returns current Unix time formatted for human readability, and this value is saved to an actual file time.html which is then served as the response to the original request.

1. If a function has arguments, those arguments appear delimited by slashes. For example,

   http://localhost:1234/two_arg/1/2

calls a function two_arg() which adds the arguments integers 1 and 2 and serves the resulting sum, 3.

1. Examples of actual functionality appear immediately below.

    http://localhost:1234/
    http://localhost:1234/index.html

Returns: The contents of file index.html.

    http://localhost:1234/help.html

Returns: The contents of file help.html.

    http://localhost:1234/subdir/file.html

Returns: The contents of file file.html in subdirectory subdir.

    http://localhost:1234/subdir/

Returns: Program error message: Path must end with ".html"; try again. Assumes a subdirectory was meant but did not find a filename to search for in that subdirectory and did not reveal anything about the content of that subdirectory.

    http://localhost:1234/subdir.html

Returns: 404 error; no such file

    http://localhost:1234/time.html
    http://localhost:1234/hello.html
    http://localhost:1234/shellfish.html
    http://localhost:1234/macguffin.html

Returns: Each of these calls the zero-argument function named (before .html). Some of these were added during the running of the server and the server became aware of them without having to be restarted.

    http://localhost:1234/one_arg/temperature

Returns: Calls a function one_arg(arg) naming "temperature" as the argument.

    http://localhost:1234/two_arg/1/2

Returns: Calls a function two_arg(arg1, arg2) adding the two integer arguments following the function name.

    http://localhost:1234/two_arg/1/2/4

Returns: Reports exception due to the wrong number of arguments for the function two_arg().

1. Method url_is_func() assumes that there are no default arguments in the function supplied, when arguments are being counted. This could be wrong. We should use more of the information from inspect.getfullargspec in populating functions.Functions.funcs.
2. Are we handling http://localhost:1234/two_arg/1/2 and http://localhost:1234/two_arg/1/2/ the same?
3. Test suite. An HTTP client would be useful for this.

• This program was written in one day (20140525) as an exercise in the Iron Forger series of Hacker School. The submitted code is tagged as_submitted, but more work has been done since then.
• Code review comments are in a directory code_review_comments/.
• Interim versions of the program are in the directory old_versions/.

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