Web Client and Server dialogue.

The HTTP response

  • The Response data contains a header as the first part and a body with the html tags to be handled by a web browser
    Example of a HTTP response header
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    HTTP/1.1 200 OK
    Date: Mon, 06 Dec 1999 20:54:26 GMT
    Server: Apache/1.3.6 (Unix)
    Last-Modified: Fri, 04 Oct 1996 14:06:11 GMT
    ETag: "2f5cd-964-381e1bd6"
    Accept-Ranges: bytes
    Content-length: 327
    Connection: close
    Content-type: text/html
    
    1. The first line, HTTP/1.1 200 OK, tells the HTTP protocol the server uses, returns status code of 200 and the status message OK.
    2. The second line indicates the current date on the server. The time is expressed in Greenwich Mean Time (GMT).
    3. The third line tells the client what kind of software the server is running . In this case, the server is Apache version 1.3.6 on Unix.
    4. The fourth line specifies the most recent modification time of the document requested by the client.
    5. The fifth line indicates an entity tag. This provides the web client with a unique identifier for the server resource.
    6. The sixth line indicates to the browser that the server processes the ability to return subsections of a document, instead of returning the entire document every time it is requested.
    7. The seventh line tells the client how many bytes are in the entity body that follow the headers.
    8. The eighth line indicates that the connection will close after the server's response.
    9. The ninth line (Content-type) tells the browser what kind of document the server is including in its response. In this case, it's HTML
    Example of a HTTP reponse body
    <HTML>
      <HEAD><TITLE>Joe's Tools</TITLE></HEAD>
      <BODY>
        <H1>Tools Page</H1>
        <H2>Hammers</H2>
        <P>Joe's Hardware Online has the largest selection of
          <A HREF="./hammers.html">hammers</A> on the earth.</P>
        <H2><A NAME=drills></A>Drills</H2>
        <P>Joe's Hardware has a complete line of cordless and corded drills,
          as well as the latest in plutonium-powered atomic drills, for those
          big around the house jobs.</P> ...
      </BODY>
    </HTML>