You may now be aware of but recursive functions are a very complex and messy thing, and most developers (myself included) don’t really like to use them. That's why when my last project required scanning a directory hierarchy for a single file (a typical recursive function task), I didn't even think about looping my own code. Instead, I used PEAR and its File_Find class directly, saving me the pain of searching through multiple levels of directory structures.
The File_Find class is designed to allow you to really do two things. First, it allows you to scan a directory tree and convert it into a PHP structure - a nested array - that reflects the parent-child relationships of the original hierarchy. Second, it allows you to search for one or more files of matching type in a directory tree. This type can be a simple string or a complex Perl rule expression; File_Find can handle either of the above formats and will return a detailed file and path for each pair. Array of information.
Initially, install the package manually, you can download it and then extract its contents into the PEAR root directory, or you can leverage the PEAR installer.
Next, create the following PHP script (Listing A) and save it in the file root directory of your web server:
PHP Class Search Locate Directory Tree Listing A
<ol class="dp-xml"> <li class="alt"><span><span class="tag"><</span><span> ?php </span></span></li><li><span>// include class </span></li><li class="alt"><span>include(”Find.php”); </span></li><li><span>// initialize finder </span></li><li class="alt"><span>$</span><span class="attribute">finder</span><span> = </span><span class="attribute-value">new</span><span> File_Find(); </span></li><li><span>// read directory tree and print </span></li><li class="alt"><span>$</span><span class="attribute">tree</span><span> = $finder-</span><span class="tag">></span><span>mapTree(”/tmp”); </span></span></li> <li><span>print_r($tree); </span></li> <li class="alt"> <span class="tag">?></span><span> </span> </li> </ol>
Here, I initialize a new File_Find() object and call its mapTree() method with a directory path. The mapTree() method reads the specified directory and generates a two-element hierarchical "array map" of it. The first element in this array lists all subdirectories found under the target directory, while the second element lists all files found. It is then possible to scan these sequences and use them in applications - for example, to reconstruct directory trees or to filter files and directories based on custom criteria.
List B is an example of the output of the above script:
PHP class search location directory tree list B
<ol class="dp-xml"> <li class="alt"><span><span>Array </span></span></li> <li><span>( </span></li> <li class="alt"> <span>[0] =</span><span class="tag">></span><span> Array </span> </li> <li><span>( </span></li> <li class="alt"> <span>[0] =</span><span class="tag">></span><span> /tmp </span> </li> <li> <span>[1] =</span><span class="tag">></span><span> /tmp/dummyA </span> </li> <li class="alt"> <span>[2] =</span><span class="tag">></span><span> /tmp/dummyB </span> </li> <li> <span>[3] =</span><span class="tag">></span><span> /tmp/dummyA/dummyC </span> </li> <li class="alt"><span>) </span></li> <li> <span>[1] =</span><span class="tag">></span><span> Array </span> </li> <li class="alt"><span>( </span></li> <li> <span>[0] =</span><span class="tag">></span><span> /tmp/data.txt </span> </li> <li class="alt"> <span>[1] =</span><span class="tag">></span><span> /tmp/dummyB/metoo.mp3 </span> </li> <li> <span>[2] =</span><span class="tag">></span><span> /tmp/dummyB/track.dat </span> </li> <li class="alt"> <span>[3] =</span><span class="tag">></span><span> /tmp/dummyA/dummyC/parrot.gif </span> </li> <li><span>) </span></li> <li class="alt"><span>) </span></li> </ol>
You can also use the mapTreeMultiple() method in another way, which recursively reads the specified directory and produces a nested array that copies its tree structure. Listing C shows you an example.
PHP class search location directory tree list C
<ol class="dp-xml"> <li class="alt"><span><span class="tag"><</span><span> ?php </span></span></li><li><span>// include class </span></li><li class="alt"><span>include(”Find.php”); </span></li><li><span>// initialize finder </span></li><li class="alt"><span>$</span><span class="attribute">finder</span><span> = </span><span class="attribute-value">new</span><span> File_Find(); </span></li><li><span>// print recursive directory tree </span></li><li class="alt"><span>$</span><span class="attribute">tree</span><span> = $finder-</span><span class="tag">></span><span>mapTreeMultiple(”/tmp”); </span></span></li> <li><span>print_r($tree); </span></li> <li class="alt"> <span class="tag">?></span><span> </span> </li> </ol>
List D shows the output results:
PHP class Search and locate the directory tree list D
<ol class="dp-xml"> <li class="alt"><span><span>Array </span></span></li> <li><span>( </span></li> <li class="alt"> <span>[0] =</span><span class="tag">></span><span> data.txt </span> </li> <li> <span>[dummyA] =</span><span class="tag">></span><span> Array </span> </li> <li class="alt"><span>( </span></li> <li> <span>[dummyC] =</span><span class="tag">></span><span> Array </span> </li> <li class="alt"><span>( </span></li> <li> <span>[0] =</span><span class="tag">></span><span> parrot.gif </span> </li> <li class="alt"><span>) </span></li> <li><span>) </span></li> <li class="alt"> <span>[dummyB] =</span><span class="tag">></span><span> Array </span> </li> <li><span>( </span></li> <li class="alt"> <span>[0] =</span><span class="tag">></span><span> metoo.mp3 </span> </li> <li> <span>[1] =</span><span class="tag">></span><span> track.dat </span> </li> <li class="alt"><span>) </span></li> <li><span>) </span></li> </ol>
Tip: You can add an optional parameter to mapTreeMultiple() to limit it to when performing recursion The number of layers to query below.
Using the glob() method, you can search in a specified directory for files matching a specific Perl-compatible regular expression. Please take a look at Listing E.
PHP class search location directory tree list E
<ol class="dp-xml"> <li class="alt"><span><span class="tag"><</span><span> ?php </span></span></li><li><span>// include class </span></li><li class="alt"><span>include(”Find.php”); </span></li><li><span>// initialize finder </span></li><li class="alt"><span>$</span><span class="attribute">finder</span><span> = </span><span class="attribute-value">new</span><span> File_Find(); </span></li><li><span>// search for matching files in named directory </span></li><li class="alt"><span>$</span><span class="attribute">results</span><span> = $finder-</span><span class="tag">></span><span>glob(”/mp3/i”, “/usr/local/stuff”, “perl”); </span></span></li> <li><span>print_r($results); </span></li> <li class="alt"> <span class="tag">?></span><span> </span> </li> </ol>
Here, the glob() method accesses all names in the specified directory with There are files with string mp3. Note my use of the i modifier, which makes the search case-insensitive, and my use of a third argument, which tells the class to use the Perl regex function instead of the default PHP function.
The File_Find class really comes into its own thanks to its search() method, which combines the capabilities of the mapTreeMultiple() and glob() methods for multi-level directory searches. Listing F is an example.
PHP class search location directory tree list F
<ol class="dp-xml"> <li class="alt"><span><span class="tag"><</span><span> ?php </span></span></li><li><span>// include class </span></li><li class="alt"><span>include(”Find.php”); </span></li><li><span>// initialize finder </span></li><li class="alt"><span>$</span><span class="attribute">finder</span><span> = </span><span class="attribute-value">new</span><span> File_Find(); </span></li><li><span>// search for matching files </span></li><li class="alt"><span>// in named directory and subdirectories </span></li><li><span>$</span><span class="attribute">results</span><span> = $finder-</span><span class="tag">></span><span>search(”/exe/i”, “/usr/local/winstuff”, “perl”); </span></span></li> <li class="alt"><span>print_r($results); </span></li> <li> <span class="tag">?></span><span> </span> </li> </ol>
Listing G shows a sample of the output:
PHP class search positioning directory tree list G
<ol class="dp-xml"> <li class="alt"><span><span>Array </span></span></li> <li><span>( </span></li> <li class="alt"> <span>[0] =</span><span class="tag">></span><span> /usr/local/winstuff/4HELP.EXE </span> </li> <li> <span>[1] =</span><span class="tag">></span><span> /usr/local/winstuff/ARJ.EXE </span> </li> <li class="alt"> <span>[2] =</span><span class="tag">></span><span> /usr/local/winstuff/bzip2.exe </span> </li> <li> <span>[3] =</span><span class="tag">></span><span> /usr/local/winstuff/CRLF.EXE </span> </li> <li class="alt"> <span>[4] =</span><span class="tag">></span><span> /usr/local/winstuff/DECODE.EXE </span> </li> <li> <span>[5] =</span><span class="tag">></span><span> /usr/local/winstuff/GREP.EXE </span> </li> <li class="alt"> <span>[6] =</span><span class="tag">></span><span> /usr/local/winstuff/GPG/gpg.exe </span> </li> <li> <span>[7] =</span><span class="tag">></span><span> /usr/local/winstuff/GPG/uninst-gnupg.exe </span> </li> <li class="alt"> <span>[8] =</span><span class="tag">></span><span> /usr/local/winstuff/GPG/WinPT.exe </span> </li> <li> <span>[9] =</span><span class="tag">></span><span> /usr/local/winstuff/Fprot/F-PROT.EXE </span> </li> <li class="alt"><span>) </span></li> </ol>
This is your recursive directory query, only four lines of code!
As you can see, File_Find makes it possible to complete a relatively complex task simply and efficiently, and you will feel minimal stress, which is why I highly recommend it to you. Next time you need to perform a file search operation on the PHP class search location directory tree, you might as well try it yourself. Happy programming!
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