Sending Image Data via HTTP Websockets in C - c

Question

I'm currently trying to build a library similar to ExpressJS in C. I have the ability to send any text (with res.send() functionality) or textually formatted file (.html, .txt, .css, etc.).
However, sending image data seems to cause a lot more trouble! I'm trying to use pretty much the exact same process I used for reading textual files. I saw this post and answer which uses a MAXLEN variable, which I would like to avoid. First, here's how I'm reading the data in:
// fread char *, goes 64 chars at a time
char *read_64 = malloc(sizeof(char) * 64);
// the entirety of the file data is placed in full_data
int *full_data_max = malloc(sizeof(int)), full_data_index = 0;
*full_data_max = 64;
char *full_data = malloc(sizeof(char) * *full_data_max);
full_data[0] = '\0';
// start reading 64 characters at a time from the file while fread gives positive feedback
size_t fread_response_length = 0;
while ((fread_response_length = fread(read_64, sizeof(char), 64, f_pt)) > 0) {
// internal array checker to make sure full_data has enough space
full_data = resize_array(full_data, full_data_max, full_data_index + 65, sizeof(char));
// copy contents of read_64 into full_data
for (int read_data_in = 0; read_data_in < fread_response_length / sizeof(char); read_data_in++) {
full_data[full_data_index + read_data_in] = read_64[read_data_in];
}
// update the entirety data current index pointer
full_data_index += fread_response_length / sizeof(char);
}
full_data[full_data_index] = '\0';
I believe the error is related to this component here. Likely something with calculating data length with fread() responses perhaps? I'll take you through the HTTP response creating as well.
I split the response sending into two components (as per the response on this question here). First I send my header, which looks good (29834 seems a bit large for image data, but that is an unjustified thought):
HTTP/1.1 200 OK
Content-Length: 29834
Content-Type: image/jpg
Connection: Keep-Alive
Access-Control-Allow-Origin: *
I send this first using the following code:
int *head_msg_len = malloc(sizeof(int));
// internal header builder that builds the aforementioned header
char *main_head_msg = create_header(status, head_msg_len, status_code, headers, data_length);
// send header
int bytes_sent = 0;
while ((bytes_sent = send(sock, main_head_msg + bytes_sent, *head_msg_len - bytes_sent / sizeof(char), 0)) < sizeof(char) * *head_msg_len);
Sending the image data (body)
Then I use a similar setup to try sending the full_data element that has the image data in it:
bytes_sent = 0;
while ((bytes_sent = send(sock, full_data + bytes_sent, full_data_index - bytes_sent, 0)) < full_data_index);
So, this all seems reasonable to me! I've even taken a look at the file original file and the file post curling, and they each start and end with the exact same sequence:
Original (| implies a skip for easy reading):
�PNG
�
IHDR��X��d�IT pHYs
|
|
|
RU�X�^Q�����땵I1`��-���
#QEQEQEQEQE~��#��&IEND�B`�
Post using curl:
�PNG
�
IHDR��X��d�IT pHYs
|
|
|
RU�X�^Q�����땵I1`��-���
#QEQEQEQEQE~��#��&IEND�B`
However, trying to open the file that was created after curling results in corruption errors. Similar issues occur on the browser as well. I'm curious if this could be an off by one or something small.
Edit:
If you would like to see the full code, check out this branch on Github.