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♦ fgets(): Reads a line from a file you specify

♦ feof(): Checks whether you have hit the end of a file you specify during a file read

♦ file(): Puts the entire contents of a file you specify into an array

Writing text to files

This section details the functions needed to access and write to a file, such as how to request access to a file from PHP with the fopen() function, write to the file using the fwrite() function, and let PHP know you are done with the file with the fclose() function.

fopen()

To do any file manipulations, you must tell PHP about the file you would like to manipulate and tell PHP how you would like to manipulate that file.

The fopen() function has two required parameters that you must pass to it: the path to the file and the type of file manipulation you would like to perform (the mode).

The fopen() function returns a connection to the requested file if it’s successful. (The connection is called a pointer — see the “Official file manipulation terminology” sidebar for more information.) If there is an error, the fopen() function returns False. Whatever the fopen() function returns (the connection or False), it should be assigned to a variable (a stream).

Here is an example of the fopen() function; see the section “Storing data in a CSV file” later in this chapter for an example of the fopen() function in action:

$fileConnection = fopen($theFile, $theMode);

In the preceding example, the file connection returned by the fopen() function is assigned to the variable $fileConnection. The variable $theFile would contain the path to a file; for example, both C:\\xampp\\htdocs\\inc\\info.txt and /inc/log.txt are valid file paths. The file must be in a place the server can access, meaning that you can put the file anywhere you could put a PHP page for the server to serve.

Although possible, you probably shouldn’t try to connect to a file in the My Documents folder or its equivalent on your operating system. You’ll need the actual file path, which can be quite convoluted. It’s also not necessary for the files you open to be in the htdocs directory. This could be useful if you want to access a file that will not be available except through your program. Use a relative reference if the file will be in the same directory as your program, or use an absolute reference if it will be somewhere else on your system. If you move your program to a remote server, you can only access files that reside on that server.

Official file manipulation terminology

If you look at the documentation for fopen(), or any of the file manipulation functions, you will see some funny terminology. To keep things simple, I decided to use more recognizable, easily understandable terms. I wanted you to know that I switched things up a little bit to give you a quick primer to help you out if you did happen to look at the official documentation or talk to a more seasoned programmer who might use the official terms.

According to the official online PHP documentation, the fopen() function returns a file pointer, and binds a named resource to a stream.

What this means is that when you use the fopen() function, it opens a file (much like you would do if you opened the file in Notepad) and returns a pointer to that file.

It’s as if you had put your mouse arrow at the beginning of the file and clicked there to create the little blinky-line cursor telling Notepad where you are focusing (where you would like to begin editing the text). The pointer is PHP’s focus on the file.

With the fopen() function, PHP’s focus is bound to a stream, which means that it is attached to a variable. When you use the fopen() function, you associate the file with a variable of your choosing. This variable is how PHP keeps track of the location of the file and keeps track of where PHP’s cursor is in the file. Normally, when you think of a stream, you might think of a one-way flow. But, in this case, the stream can either be read into the program character by character, line by line, or you