Add to Parse

Back in the request package, we're going to update our (r *Request) parse method to parse the headers in addition to the request line. Let's start with some new tests.

1. Create a new test function. This one will focus on parsing headers correctly. Here are a couple of test cases:

   // Test: Standard Headers
   reader := &chunkReader{
       data:            "GET / HTTP/1.1\r\nHost: localhost:42069\r\nUser-Agent: curl/7.81.0\r\nAccept: */*\r\n\r\n",
       numBytesPerRead: 3,
   }
   r, err := RequestFromReader(reader)
   require.NoError(t, err)
   require.NotNil(t, r)
   assert.Equal(t, "localhost:42069", r.Headers["host"])
   assert.Equal(t, "curl/7.81.0", r.Headers["user-agent"])
   assert.Equal(t, "*/*", r.Headers["accept"])
   
   // Test: Malformed Header
   reader = &chunkReader{
       data:            "GET / HTTP/1.1\r\nHost localhost:42069\r\n\r\n",
       numBytesPerRead: 3,
   }
   r, err = RequestFromReader(reader)
   require.Error(t, err)
   

2. Add some more cases of your own to test for various edge cases with the headers. Here are the names of some of my additional test cases:

   • "Standard Headers"
   • "Empty Headers"
   • "Malformed Header"
   • "Duplicate Headers"
   • "Case Insensitive Headers"
   • "Missing End of Headers"

3. Add a new requestStateParsingHeaders to our "enum" of states.

4. In the (r *Request) parse method, when you're done parsing the request line, switch to the new requestStateParsingHeaders instead of the done state.

5. In the (r *Request) parse method, when in the requestStateParsingHeaders state, parse the headers.

There's a big change here that can be tricky: parsing the headers may need to happen successfully multiple times, unlike the request line, which we always parse in one go. This is also true of the request body, which we'll cover later. So, because both the headers and the body will need to support multiple "parses" for each "read", I did a little refactor.

I did not change my .parse method signature, but I did move a lot of the functionality to a new method. My .parse now keeps track of the totalBytesParsed, and then starts a loop:

totalBytesParsed := 0
for r.state != requestStateDone {
    n, err := r.parseSingle(data[totalBytesParsed:])
    // ...

Again, I'm doing this because the header parsing may need to happen multiple times for the same chunk of data because we can have multiple headers in the same chunk. So, I moved the switch/case logic that handles the actual parsing based on the state and moved it into a new nested method called parseSingle.

When you're done parsing all the headers, set the state to requestStateDone and return the total number of bytes parsed, just like before.

Run and submit the CLI tests.