mobicms/captcha

This library is a simple PHP CAPTCHA. Prevent form spam by generating random Captcha images.

Major features:

• lightweight and fast
• not create any temporary files
• there are many settings that allow you to change the look of the picture
• you can use your own font sets

Example:

Installation

The preferred method of installation is via Composer. Run the following command to install the package and add it as a requirement to your project's composer.json:

composer require mobicms/captcha

Simply usage (v.5)

• Display in form:

<?php
$captcha = new Mobicms\Captcha\Image();
$_SESSION['code'] = $captcha->getCode();
?>

<form method="post">
<!-- ... -->
<img alt="Verification code" src="<?= $captcha->getImage() ?>">
<input type="text" size="5" name="code">
<!-- ... -->
</form>

• Check whether the entered code is correct:

$result = filter_input(INPUT_POST, 'code');
$session = filter_input(INPUT_SESSION, 'code');

if ($result !== null && $session !== null) {
    if (strtolower($result) == strtolower($session)) {
        // CAPTCHA code is correct
    } else {
        // CAPTCHA code is incorrect, show an error to the user
    }
}

Customization (v.5)

You can change CAPTCHA settings through \Mobicms\Captcha\Image class properties.

Image: resizing

int $imageWidth, int $imageHeight
Keep in mind that the width of the image will affect the density of the text.
If the characters are very creeping on top of each other and become illegible, then increase the width of the image, reduce the length of the verification code, or the font size.

$captcha = new Mobicms\Captcha\Image();

// Set the image width (default: 190)
$captcha->imageWidth = 250;
// Set the image height (default: 90)
$captcha->imageHeight = 100;

Image: default font size

int $defaultFontSize
This setting affects the size of all fonts used.

Image: fonts mixer

bool $fontMix
If this parameter is set to TRUE (default), a random font will be used for each character in the image.

If you set it to FALSE, then a single, randomly selected font will be used for all characters in the image.

Image: fonts folders

array $fontFolders
You can use your own set of TTF fonts. To do this, specify one or more folders in the array where .ttf font files are located. Keep in mind that this package already has some fonts. If you plan to use them, then merge the arrays.

$captcha = new Mobicms\Captcha\Image();

$captcha->fontFolders = array_merge(
    // Using built-in fonts 
    $captcha->fontFolders,

    // Specifying your font folders
    ['folder1', 'folder2']
);

Image: adjust font

array $fontsTune
Some fonts may have a size that looks too small or large compared to others. In this case, you need to specify an adjustment relative to the default size. Also, if necessary, you can force the specified font to use only uppercase or lowercase characters.

Adjustment parameters are passed to the $fontsTune class property as an array.
Keep in mind that the class already has some adjustments, so if you use fonts from this package, then combine your array of adjustments with an array of $fontsTune properties.

$captcha = new Mobicms\Captcha\Image();

$adjust = [
    // Specify the name of the font file
    'myfont1.ttf' => [
        // Specify the relative font size.
        // It will be summarized with the default size specified in the $defaultFontSize property
        // In this case, the font will be used: 30+16=46
        'size' => 16, // Optional
        // Forcing the use of only lowercase characters of the specified font
        'case' => \Mobicms\Captcha\Image::FONT_CASE_LOWER, // Optional
    ],

    'myfont2.ttf' => [
        // Forcing the use of only uppercase characters of the specified font
        'case' => \Mobicms\Captcha\Image::FONT_CASE_UPPER,
    ],

    'myfont3.ttf' => [
        // Font size will be decreased by 8
        'size' => -8,
    ],

    'myfont4.ttf' => [
        // Font size will be increased by 4
        'size' => 4,
    ],
];

$captcha->fontsTune = array_merge($captcha->fontsTune, $adjust);

Verification code: use your own

The Image class already has the ability to generate validation code, which will be sufficient in most use cases. However, if necessary, you can generate the validation code yourself and then pass string to the constructor when the Image class is initialized:

$code = 'FooBar';
$captcha = new Mobicms\Captcha\Image($code);

Verification code: length

int $lengthMin, int $lengthMax
The length of the generated code string will be randomly between the specified minimum and maximum values.

Verification code: character Set

string $characterSet
In this string you can specify a set of characters that will be used randomly when generating the verification code. Avoid using characters that can be interpreted ambiguously, such as O (letter) and 0 (number).

Verification code: excluded сombinations

string $excludedCombinationsPattern
You can use a pattern to specify combinations of adjacent characters that should not appear next to each other. For example, rn can be interpreted as m, and so on...

Contributing

Contributions are welcome! Please read Contributing for details.

In our development, we follow the principles of YAGNI and KISS. The source code should not have extra unnecessary functionality and should be as simple and efficient as possible.

License

This package is licensed for use under the MIT License (MIT).
Please see LICENSE for more information.

Our links

• mobiCMS Project website and support forum
• GitHub mobiCMS project repositories
• Twitter