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# README                                                                       #
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# Implementation of a Lisod Server                                             #
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# Authors:                                                                     #
# Yunie Mao <ym224@cornell.edu>                                                #
# David (Zheyuan) Gu <zg245@cornell.edu >                                      #
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Description of Files
      Our lisod server is designed with 4 core components: 
      lisod.c -- main source file
      log.h -- header file for log
      log.c -- source c file for log 
      parse.h -- header file for parse
      parse.c -- sourse c file for parse
      process_request.h -- header file for process request
      process_request.c -- sourse c file for process request


How to Run
      The server is built based on the files listed above. 
      Simply run "make lisod" in a linux terminal to make the lisod an executable file, 
      then run "./lisod" with the http port, www resourse path and the log file name in your terminal to execute the file.
      After the file compiles, you can connect to the lisod server!
      
      Lisod server is open and listens to the client. 
      1) For Checkpoint 1, the starter code given was able to create an echo server which is able to listen to only one client
      at a time and return client's input. The goal for Checkpoint 1 is to create a echo_server to simultaneously listen to
      multiple clients. 
      2) For Checkpoint 2, the server has implemented three HTTP methods, HEAD, GET, and POST, in which each has its
      functionalities. 
        GET requests a specified resource; it should not have any side effects other than retrieval.
        HEAD asks for an identical response as GET, without the actual body - no bytes from the requested resource.
        POST submits data to be processed to an identified resource; the data is in the body of this request.



Design and Implementation
      In this project, multithread functionality is controlled by select(). With each new client comes in, the server will
      create a seperate file descriptor to listen to the client. This will avoid a single line traffic when multiple clients
      are visiting the server at the same time. 
      
      Everytime the server gets something from the client when it's running, it goes to the main function and check if a
      socket is created. If it's a valid request, the server will call parse() function in parse.c to analyze the incoming
      request. Then in the main function, process_http_request() in process_request.c was called. The function takes care of
      HEAD, GET, and POST method. Finally, write_log() was called to write the log in a logfile and send() was called to send
      the information back to the client.