Skip to main content

How File Processing is done in PHP?

In the previous post’s (Designing a Simple Order Form Application in PHP) example we implemented the file I/O for storing order information without discussing about it.

For those of you who were eager to know more about PHP File I/O read along, this post has it.

File processing requires the following steps:

  1. Opening a file
  2. Doing the operation
  3. Closing the file

Opening a file

First of all we have to open the file before any operation (reading/writing) can be done.

If you remember the previous post Designing a Simple Order Form Application in PHP, we had this line

//open file
$fp=fopen("orders.txt","a");

There we’re opening a file named “orders.txt” in the “append” file mode. File modes tell PHP what we want to do with the file.

Some of the commonly used files modes along with what they mean is listed below:

r For reading only, reading begins from the start of the file
r+ Reading and writing, beginning from the start of the file
w For writing only. Creates the file if it doesn’t exist. Deletes existing content if it exists.
w+ For writing and writing. Creates the file if it doesn’t exist. Deletes existing content if it exists.
a For appending (writing) beginning from the end of the existing data. Creates the file if it doesn’t exist.
a+ For appending (writing) and reading beginning from the end of the existing data. Creates the file if it doesn’t exist.

Doing the operation

Once the file is opened, we can any operation we want on it (of course those which are supported for that file mode).

In the previous post Designing a Simple Order Form Application in PHP, we used

//write the data to the opened file
fputs($fp,$data);

Here first argument is the file resource pointer and second is the string to be written to that file (pointed to by $fp).

fgets () is another function, it is used to read back information from file. It has the following form:

$data=fgets($fp,999);

It reads one line at a time marked by “\n” which here gets stored in the variable $data.

One line can also be when it encounters and EOF (End Of File) or when the line has length greater than the maximum length (999) to be read.

Besides these functions that operate on a file, there are many others but we won’t be discussing any more of them here.

Closing the file

after all the operations have been done we need to close the file. It is done like below:

//close the file
fclose($fp);

$fp is a file resource that needs to be closed.

It tells PHP and the Operating System that we’ve performed the operations we needed and it’s safe to close our link from that file.

Related Articles:

Labels:

Popular posts from this blog

The Best Way(s) to Comment out PHP/HTML Code

PHP supports various styles of comments. Please check the following example: <?php // Single line comment code (); # Single line Comment code2 (); /* Multi Line comment code(); The code inside doesn't run */ // /* This doesn NOT start a multi-line comment block /* Multi line comment block The following line still ends the multi-line comment block //*/ The " # " comment style, though, is rarely used. Do note, in the example, that anything (even a multi-block comment /* ) after a " // " or " # " is a comment, and /* */ around any single-line comment overrides it. This information will come in handy when we learn about some neat tricks next. Comment out PHP Code Blocks Check the following code <?php //* Toggle line if ( 1 ) {      // } else {   ...
Read more

How to Create an HTML Form Linked with MySQL Database in PHP

If you're looking for example code and detailed discussion on how to create an HTML form that stores data in a MySQL database using PHP then this post might be what you're looking for. I assume that you're familiar with basic HTML, CSS, PHP coding, and  MySQL. I am going to divide this small project into two parts: The HTML form itself that takes input from the user and the PHP script that saves it into the database A table that displays the user-added data that has been saved in the database. We'll be dealing with the first part in this tutorial. Again I'd like to break this problem into a few parts so that it's easier for you to understand and probably gives you an insight into how breaking up a problem into smaller chunks can help make things clearer in your mind. Let's think about it, there is an HTML form (that is HTML code), then there is the PHP code that deals with the user-input data, and the MySQL database itself. For this tutorial, we'll b...
Read more

Fix For Toshiba Satellite "RTC Battery is Low" Error (with Pictures)

RTC Battery is Low Error on a Toshiba Satellite laptop "RTC Battery is Low..." An error message flashing while you try to boot your laptop is enough to panic many people. But worry not! "RTC Battery" stands for Real-Time Clock battery which almost all laptops and PCs have on their motherboard to power the clock and sometimes to also keep the CMOS settings from getting erased while the system is switched off.  It is not uncommon for these batteries to last for years before requiring a replacement as the clock consumes very less power. And contrary to what some people tell you - they are not rechargeable or getting charged while your computer or laptop is running. In this article, we'll learn everything about RTC batteries and how to fix the error on your Toshiba Satellite laptop. What is an RTC Battery? RTC or CMOS batteries are small coin-shaped lithium batteries with a 3-volts output. Most laptops use ...
Read more