TINYHTTPD Reading notes

1. Introduction

TINYHTTPD is an open-source, ultra-lightweight HTTP server that reads its source code and can learn more about HTTP protocols and micro-servers.

Source link;

Reference Blog: tinyhttpd Source Analysis

2. Notes

------------------------------------------------------May 7, 2016 21:31:35--------------------------------------- -------------

A function prototype catalog that lists all the function prototypes needed for the entire project

1 voidAccept_request (void*);2 voidBad_request (int);3 voidCatint, FILE *);4 voidCannot_execute (int);5 voidError_die (Const Char*);6 voidEXECUTE_CGI (int,Const Char*,Const Char*,Const Char*);7 intGet_line (int,Char*,int);8 voidHeadersint,Const Char*);9 voidNot_found (int);Ten voidServe_file (int,Const Char*); One intStartup (U_short *); A voidUnimplemented (int);

The role of each function in the project's Readme file has a simple description:

Function	Describe
Accept_request	Handles an HTTP request that is heard from a socket, where a large part of the server processing request process can be represented
Bad_request	Return to client this is an error request, HTTP status?
Cat	Read a file on the server write to the socket socket
Cannot_execute	Primary handling of errors that occur when executing CGI programs
Error_die	Write the error message to Perror and exit
execute_cgi	The process of running a CGI program is also a major function
Get_line	Read a line of the socket, the carriage return line, and so on are unified for the end of the line break
Headers	Writes the header of the HTTP response to the socket
Not_found	Case where the requested file was not found in the main process
Sever_file	Call cat to return the server file to the browser
Startup	Initialize the httpd service, including setting up sockets, binding ports, listening, etc.
unimplemented	Returned to the browser indicates that the method used to receive the HTTP request is not supported

Suggested Source reading order:

Main--->startup--->accept_request--->execute_cgi

In this order, the entire server workflow is cleared.

Main function

1 intMainvoid)2 {3     intServer_sock =-1;4U_short port =4000;5     intClient_sock =-1;6     structsockaddr_in client_name;7socklen_t Client_name_len =sizeof(client_name);8 pthread_t Newthread;9 TenServer_sock = Startup (&port); Oneprintf"httpd running on port%d\n", port); A  -      while(1) -     { theClient_sock =Accept (Server_sock, -(structSOCKADDR *) &Client_name, -&Client_name_len); -         if(Client_sock = =-1) +Error_die ("Accept"); -         /*accept_request (client_sock);*/ +         if(Pthread_create (&newthread, NULL, (void*) Accept_request, (void*) &client_sock)! =0) APerror ("pthread_create"); at     } -  - Close (server_sock); -  -     return(0); -}

3–7 line is the definition of socket related variables, the detailed introduction of the socket can be online access to relevant information or read the book "UNIX Network Programming";

The 10th line calls the startup function, and the contents of the function follow a brief explanation;

第13-23 line, listen to the client to the service side of the request connection, when a connection is received, create a thread to execute the corresponding request, the thread entry function is Accept_request, but also about the use of Linux pthread_create need to pay attention to some of the details of the problem.

Line 25th closes the socket on the server side.

startup function

The function parameter is a port number that is used to create a TCP socket for the corresponding port number

1 intStartup (U_short *Port)2 {3     inthttpd =0;4     structsockaddr_in name;5 6httpd = socket (pf_inet, Sock_stream,0);7     if(httpd = =-1)8Error_die ("Socket");9memset (&name,0,sizeof(name));Tenname.sin_family =af_inet; OneName.sin_port = htons (*port); ANAME.SIN_ADDR.S_ADDR =htonl (inaddr_any); -     if(Bind (httpd, (structSOCKADDR *) &name,sizeof(name)) <0) -Error_die ("Bind"); the     if(*port = =0)/*if dynamically allocating a port*/ -     { -socklen_t Namelen =sizeof(name); -         if(GetSockName (httpd, (structSOCKADDR *) &name, &namelen) = =-1) +Error_die ("getsockname"); -*port =Ntohs (name.sin_port); +     } A     if(Listen (httpd,5) <0) atError_die ("Listen"); -     return(httpd); -}

Line 6th creates a socket socket, because its parameters are sock_stream, so the TCP socket is created;

7–8 line, if the socket creation is unsuccessful, then call the encapsulated error handler Error_die, which is simpler, is to print the error message and end the entire program.

第13-23 is the basic process of creating socket server, first bind operation, then listen operation;

TINYHTTPD Reading notes