6 allow prefixing image sources (#7)

It's possible to prefix image sources. Thanks @juripetersen

config/config.php

@@ -42,4 +42,17 @@
         ],
     ],
 
+    /*
+   |--------------------------------------------------------------------------
+   | Images
+   |--------------------------------------------------------------------------
+   |
+   | If fetching images from an external repository, you may wish to prefix
+   | your image paths with a prefix to automatically convert a relative url
+   | to an absolute url.
+   |
+   */
+    'images' => [
+        //  'prefix' => 'https://your-prefix.com/',
+    ],
 ];

src/Markdown/AddCustomHtmlClasses.php

@@ -6,13 +6,13 @@ class AddCustomHtmlClasses
 {
     public string $content;
     public string $style;
-    public array $styleset;
+    public array $styleSet;
 
     public function __construct(string $content, string $style)
     {
         $this->content = $content;
         $this->style = $style;
-        $this->styleset = $this->getStyleSet();
+        $this->styleSet = $this->getStyleSet();
     }
 
     /**
@@ -21,7 +21,7 @@ public function __construct(string $content, string $style)
      */
     public function handle(): string
     {
-        foreach ($this->styleset as $tag => $class) {
+        foreach ($this->styleSet as $tag => $class) {
             $this->content = str_replace($this->tagFilter($tag), $this->replaceTag($tag, $class), $this->content);
         }
 
@@ -44,14 +44,10 @@ private function replaceTag(string $tag, string $class): string
         return "<{$tag} class=\"{$class}\"";
     }
 
-    private function getStyleset(): array
+    private function getStyleSet(): array
     {
         $configPath = 'markdown.styles.'.$this->style;
 
-        if (!config()->has($configPath)) {
-            return [];
-        }
-
-        return config($configPath);
+        return config($configPath, []);
     }
 }

src/Markdown/CommonMarkRepository.php

@@ -18,11 +18,16 @@ public function parse(string $content): string
     {
         $content = $this->parser->convertToHtml($content);
 
-        return (new AddCustomHtmlClasses($content, $this->style))->handle();
+        return (new PrefixImageSources(
+            (new AddCustomHtmlClasses($content, $this->style))->handle()
+        )
+        )->handle();
     }
 
     public function style(string $style): self
     {
+        $this->style = $style;
+
         return $this;
     }
 }

src/Markdown/PrefixImageSources.php

@@ -0,0 +1,94 @@
+<?php
+
+namespace VV\Markdown\Markdown;
+
+use Illuminate\Support\Arr;
+use Illuminate\Support\Str;
+
+class PrefixImageSources
+{
+    public string $content;
+
+    public function __construct(string $content)
+    {
+        $this->content = $content;
+    }
+
+    /**
+     * Find all image sources in the html content and replace all absolute paths with a configurable url that is prefixed to it.
+     */
+    public function handle()
+    {
+        if ($this->getPrefixUrl()) {
+            $this->findImageSources($this->findImages($this->content));
+        }
+
+        return $this->content;
+    }
+
+    /**
+     * Iterate over the html and find all images.
+     */
+    private function findImages(string $htmlContent): array
+    {
+        preg_match_all('/<img[^>]+>/i', $htmlContent, $result);
+
+        return Arr::flatten($result);
+    }
+
+    /**
+     * Iterate over all sources and prefix them with the configurable url.
+     */
+    private function findImageSources(array $htmlImages): void
+    {
+        foreach ($htmlImages as $image) {
+            preg_match('/src=(?:"[^"]*")/i', $image, $source);
+
+            $source = $source[0] ?? null;
+
+            if ($source && !$this->isAbsolutePath($source)) {
+                $this->content = str_replace($source, $this->insertPrefix($source), $this->content);
+            }
+        }
+    }
+
+    /**
+     * Add prefix to image source.
+     */
+    private function insertPrefix(string $source): string
+    {
+        $source = str_replace('src="', '', $source);
+
+        if (Str::startsWith($source, '/')) {
+            $source = Str::substr($source, 1);
+        }
+
+        $prefix = $this->getPrefixUrl();
+
+        return 'src="'.$prefix.$source;
+    }
+
+    /**
+     * Load Prefix URL from config.
+     */
+    private function getPrefixUrl(): ?string
+    {
+        $prefix = config('markdown.images.prefix', null);
+
+        if ($prefix) {
+            $prefix = Str::finish($prefix, '/');
+        }
+
+        return $prefix;
+    }
+
+    /**
+     * Check if source is a absolute path or a complete url.
+     */
+    private function isAbsolutePath(string $source): bool
+    {
+        return Str::contains($source, 'https://')
+        || Str::contains($source, 'http://')
+        || Str::contains($source, 'ftp://');
+    }
+}

tests/Unit/CommonMarkTest.php

@@ -3,6 +3,7 @@
 namespace VV\Markdown\Tests\Unit;
 
 use VV\Markdown\Facades\Markdown;
+use VV\Markdown\Markdown\PrefixImageSources;
 use VV\Markdown\Tests\TestCase;
 
 class CommonMarkTest extends TestCase
@@ -42,8 +43,9 @@ public function it_can_add_a_html_class_to_a_paragraph()
     public function it_can_parse_tables()
     {
         $toParse = 'th | th(center) | th(right)
----|:----------:|----------:
-td | td         | td';
+                    ---|:----------:|----------:
+                    td | td         | td';
+
         $result = '<table>';
 
         $this->assertStringcontainsString($result, Markdown::parse($toParse));
@@ -55,8 +57,9 @@ public function it_can_add_a_css_class_to_a_table()
         config()->set('markdown.styles.default.table', 'mb-2');
 
         $toParse = 'th | th(center) | th(right)
----|:----------:|----------:
-td | td         | td';
+                    ---|:----------:|----------:
+                    td | td         | td';
+
         $result = '<table class="mb-2">';
 
         $this->assertStringcontainsString($result, Markdown::parse($toParse));
@@ -79,4 +82,33 @@ public function it_can_parse_lists()
 
         $this->assertStringcontainsString($result, Markdown::parse($toParse));
     }
+
+    /** @test */
+    public function it_prefixes_relative_image_sources()
+    {
+        config()->set('markdown.images.prefix', 'https://git.visuellverstehen.de/visuel/wiki/-/raw/main');
+        $result = '<img src="/uploads/7a9a2cea1fe762a59ae72cb1fd78e7bd/screenshot_5.png" alt="screenshot_5" />';
+
+        $prefixed = (new PrefixImageSources($result))->handle();
+        $this->assertStringContainsString('src="https://git.visuellverstehen.de/visuel/wiki/-/raw/main/uploads/7a9a2cea1fe762a59ae72cb1fd78e7bd/screenshot_5.png"', $prefixed);
+    }
+
+    /** @test */
+    public function it_does_not_prefix_if_config_empty()
+    {
+        $result = '<img src="/uploads/7a9a2cea1fe762a59ae72cb1fd78e7bd/screenshot_5.png" alt="screenshot_5" />';
+
+        $prefixed = (new PrefixImageSources($result))->handle();
+        $this->assertEquals($result, $prefixed);
+    }
+
+    /** @test */
+    public function it_does_not_prefix_complete_urls()
+    {
+        config()->set('markdown.images.prefix', 'https://git.visuellverstehen.de/visuel/wiki/-/raw/main');
+        $result = '<img src="https://www.visuellverstehen.de/fileadmin/_processed_/b/3/csm_frs-webapp-ui-ux-design-entwicklung-webbasierte-anwendung-digital-header-visuellverstehen-flensburg-werbeagentur-kommunikationsagentur-internetagentur_7b5cbde98a.jpg" alt="screenshot_5" />';
+
+        $prefixed = (new PrefixImageSources($result))->handle();
+        $this->assertStringNotContainsString('https://git.visuellverstehen.de/visuel/wiki/-/raw/main', $prefixed);
+    }
 }