The date is in the format YYYY-MM-DD. Time is in the format HH:MM:UUUUUU. The
last six digits of time are the seconds and microseconds. The host is the name of the
server and pid is the process identifier. The type is a special code described in Table
22-1. The rest of the line is a message terminated with a linefeed.
Using the remote debugger is as simple as executing a PHP script and watching the
debug information appear in the port listener output.
Table 22-1. Debugging Types
Type Descriptionend (^) The end of an error message.
frames (^) The number of frames in the call stack.
functionThe name of the function where the error occurred.
locationThe filename and line number that generated the error message.
message (^) A PHP error message.
start This type signifies the beginning of a debugging message. The data-
message for this line will be the type of error.
Simulating HTTP Connections
When writing PHP scripts, it is not necessary to understand every detail of the HTTP
protocol. I would be straying to include a treatise here, but you ought to have enough
understanding so that you could simulate a connect by using telnet. You may know that
Web servers listen on port 80 by default. HTTP is a text-based protocol, so it's not hard to
telnet directly to a Web server and type a simple request. HTTP has several commands
that should be familiar; GET and POST are used most often. HEAD is a command that
returns just the headers for a request. Browsers use this command to test whether they
really want to get an entire document.
It is especially helpful to simulate an HTTP connection when your script sends custom
headers. Figure 22-2 is an example showing a request I made to the PHP home page.
The text in bold is what I typed. The remote server returned everything else.
Figure 22.2. Simulating an HTTP Connection