Re: [lwip-users] Pulling data from a server using HTTP with lwIP

[Robert Wood]

Well, I am certainly no expert on HTTP, *but*, if I look at how things 
work with my computer, when it requests a packet from my board there is 
only the SYN, SYN ACK, ACK handshake before the computer sends the GET 
command.

Now, when my board is the client, the issue I have is not [yet] whether 
the GET is working properly.

What is happening when lwIP board is client and desktop is server:

If I establish a connection from the board to the desktop and do not 
send a GET request, then lwIP does the SYN, SYN ACK, ACK handshake just 
fine.

If I add the [potentially incorrect] GET request, the SYNN is sent, the 
SYN ACK is received, but my board running lwIP does not send the ACK out 
to the desktop.

You may well be totally correct that my GET line is incomplete, I cannot 
find any details on exactly how it should be, but I don't think that is 
the main issue at the moment. I'm happy to be told I'm talking nonsense 
though.

Thanks!



On 13/11/14 11:21, Simon Goldschmidt wrote:
> Robert Wood wrote:
> > Hmmmm. I seem to be wrong, It *does* send out the ACK. I took out these
> > lines:
> > strcpy(GetString,"GET /index.html HTTP/1.1\r\n");
> > netconn_write(xNetConn,GetString,sizeof(GetString),NETCONN_NOCOPY);
>
> As you seem to be trying to implement a HTTP client: are you familiar with the 
> HTTP protocol? I'm not sure the single line is enough for HTTP 1.1 (it should 
> be for 0.9), but at least you need a double line-break to inform the server 
> that this is the end of the HTTP header.
>
> I'd suggest reading a bit more on  HTTP.
>
> Simon
>
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