Web Client Programming with Perl-Chapter 4: The Socket Library- P1

... fully compliant with the HTTP specs, the web server won't understand you! Perhaps your web client works with one web server but not another. Or maybe your web client works most of the time, but ... etc.). Initially, the server uses the socket( ) system call to create the socket, and the bind( ) call to assign the socket to a particular port on the ho...

Ngày tải lên: 20/10/2013, 10:15

... protocol, in which the client makes a request, the server responds, and the transaction is then finished. The client initiates the transaction as follows: 1. First, the client contacts the server ... determines that the client used a POST method, processes the URL, executes the program associated with the URL, and pipes the client& apos;s entity-body to...

Ngày tải lên: 26/01/2014, 07:20

... Chapter 4: The Socket Library- P2 Now we wait for a response from the server. We read in the response and selectively echo it out, where we look at the $response, $header, and ... open_TCP('F', $the_ url[1], $the_ url[2])) { print "Error connecting to web server: $the_ url[1]\n"; exit(-1); } # request the path of the document to get print F "GET $t...

Ngày tải lên: 20/10/2013, 10:15

... are useful for client programming. The LWP Module The LWP module, in the context of web clients, performs client requests over the network. There are 10 classes in all within the LWP module, ... a client/ server negotiation.  The LWP module is the core of all web client programs. It allows the client to communicate over the network with the server.  T...

Ngày tải lên: 24/10/2013, 08:15

... invoked with no parameters, this returns the default port for the URL defined in the object. The default port is based on the scheme used. Even if the port for the URL is explicitly changed by the ... Since we're programming a web robot, the name of the robot and the email address of the user are mandatory. So, we pass that information to the LWP::RobotU...

Ngày tải lên: 24/10/2013, 08:15

... example, the browser is given the following URL: http://hypothetical.ora.com/ The browser interprets the URL as follows: http:// In the first part of the URL, you told the browser to use HTTP, the ... In the third line, beginning with the string User-Agent, the client identifies itself as Mozilla (Netscape) version 3.0, running on Windows NT. 4. The fourth l...

Ngày tải lên: 26/01/2014, 07:20

... server response In the server response, the general header and entity headers are the same as those used in the client request. The entity-body is like the one used in the client request, except ... is using. The status code indicates the result of the request, and the reason phrase is a human-readable description of the status-code. The response header t...

Ngày tải lên: 26/01/2014, 07:20

... accommodate client- side caching of documents, the client can use the If- Modified-Since header with the GET method. When using this option, the client requests the server to send the requested ... finishes. The close parameter signifies that either the client or server wishes to end the connection (i.e., this is the last transaction). The keep-alive parameter s...

Ngày tải lên: 17/10/2013, 19:15

... let's center on another chunk of code that changed from the sockets version of hgrepurl. In Chapter 4, the raw sockets version checked the response code and then skipped over the HTTP headers: ... > tags in the response. 4. If "Delivered To : " shows up in the reply (with or without text after the colon), the query was successful but the document is no...

Ngày tải lên: 28/10/2013, 15:15

... For the not _web( ), local( ), and remote( ) methods, a similar associative array is returned, where the URL is a key in the array and denotes that the URL is not HTTP-based, is local to the web ... local to the web server, in that order. The type( ) method returns an associate array of URLs, where the value of each URL hash contains the content-type for the URL. An...

Ngày tải lên: 28/10/2013, 15:15