ImagePreview
extends AbstractPlugin
in package
Detects, if there could be created an image preview for a given URL, downloads it and appends it as a custom attribute to the blocked HTML tag so the visual content blocker could create something cool.
- You need to pass a
setCache
to the plugin instance, otherwise the mechanism does not track any URLs. The purpose of the headless content blocker is to block external URLs, and we do not want to use an external URL as image preview! - Your
AbstractBlockable
needs to implementImagePreviewBlockable
interface to determine if thumbnails should be loaded for the blocked content!
Table of Contents
Constants
- HTML_ATTRIBUTE_TO_FETCH_URL_FROM = 'hcb-fetch-image-from'
- HTML_ATTRIBUTE_TO_FETCH_URL_FROM_ALTERNATIVE = 'hcb-fetch-image-from-alt'
- SKIP_EMBED_URL_EXTENSIONS = ['js', 'css', 'zip', 'pdf']
Properties
- $attributesToCheckForUrl : array<string|int, string>
- A list of possible link attributes.
- $cache : ImagePreviewCache
- ImagePreviewCache.
- $headlessContentBlocker : mixed
- $htmlHeadThumbnailParser : HtmlHeadThumbnailParser
- HtmlHeadThumbnailParser.
- $revertAttributesToCachedUrl : array<string|int, string>
- See `addRevertAttribute`.
Methods
- __construct() : mixed
- C'tor.
- addRevertAttribute() : mixed
- A list of selector syntax strings which should be reverted to the cached URL for all transformed attributes.
- afterSetup() : mixed
- The content blocker got setup completely.
- beforeMatch() : mixed
- Called before a match got found.
- blockableStringExpression() : string
- Allows to modify the passed string expression to a blockable.
- blockedMatch() : mixed
- See `AbstractPlugin`.
- checkResult() : BlockedResult
- Special case: Read attribute of the original embed URL if it got passed via a custom attribute.
- fetchMetadata() : mixed
- Use multiple mechanism to extract a thumbnail from any URL. It returns an map of URL => thumbnail, and if a thumbnail got not found it is no longer part of the returned map.
- getCache() : mixed
- Getter.
- getHeadlessContentBlocker() : mixed
- Getter.
- getWriteJson() : mixed
- Create the result for the HTML attribute which our unblocker can consume.
- init() : mixed
- Init.
- inlineStyleBlockRule() : bool
- Decide if a URL in a CSS rule should be blocked.
- inlineStyleModifyDocuments() : bool
- Allows to modify blocked CSS documents.
- inlineStyleShouldBeExtracted() : bool
- Do not extract blocked rules of a CSS inline script to a second document.
- keepAlwaysAttributes() : array<string|int, string>
- Keep attributes for a specific match.
- modifyHtmlAfterProcessing() : mixed
- Allows to modify the HTML after the content blocker has done its job.
- notBlockedMatch() : mixed
- Called after a match got not blocked. Opposite of `blockedMatch`.
- revertTransformAttributeOnMatch() : mixed
- When a match with `consent-thumbnail is found, revert the transformation of the attribute.
- setCache() : mixed
- Setter.
- setup() : mixed
- Before the content blocker gets setup.
- skipInlineScriptVariableAssignment() : array<string|int, string>
- Skip inline script by variable name.
- visualParent() : bool|string|number
- Set a visual parent for a specific match.
- findUrlForSpecialMatch() : mixed
- Find an embed URL for a special match.
- isValidEmbedUrl() : mixed
- Check if a given embed URL is valid.
- revertTransformAttribute() : mixed
- Revert the transformation of a URL attribute when we have found a thumbnail and it is cached.
Constants
HTML_ATTRIBUTE_TO_FETCH_URL_FROM
public
mixed
HTML_ATTRIBUTE_TO_FETCH_URL_FROM
= 'hcb-fetch-image-from'
HTML_ATTRIBUTE_TO_FETCH_URL_FROM_ALTERNATIVE
public
mixed
HTML_ATTRIBUTE_TO_FETCH_URL_FROM_ALTERNATIVE
= 'hcb-fetch-image-from-alt'
SKIP_EMBED_URL_EXTENSIONS
public
mixed
SKIP_EMBED_URL_EXTENSIONS
= ['js', 'css', 'zip', 'pdf']
Properties
$attributesToCheckForUrl
A list of possible link attributes.
private
array<string|int, string>
$attributesToCheckForUrl
= []
$cache
ImagePreviewCache.
private
ImagePreviewCache
$cache
$headlessContentBlocker
private
mixed
$headlessContentBlocker
$htmlHeadThumbnailParser
HtmlHeadThumbnailParser.
private
HtmlHeadThumbnailParser
$htmlHeadThumbnailParser
$revertAttributesToCachedUrl
See `addRevertAttribute`.
private
array<string|int, string>
$revertAttributesToCachedUrl
= []
Methods
__construct()
C'tor.
public
final __construct(HeadlessContentBlocker $headlessContentBlocker) : mixed
Parameters
- $headlessContentBlocker : HeadlessContentBlocker
Tags
addRevertAttribute()
A list of selector syntax strings which should be reverted to the cached URL for all transformed attributes.
public
addRevertAttribute(string $selectorSyntax) : mixed
E.g. div[class*="et_pb_video_slider_item_"]
will revert e.g. consent-original-data-image
back to data-image
with the cached URL.
Parameters
- $selectorSyntax : string
afterSetup()
The content blocker got setup completely.
public
afterSetup() : mixed
beforeMatch()
Called before a match got found.
public
beforeMatch(AbstractMatcher $matcher, AbstractMatch $match) : mixed
Parameters
- $matcher : AbstractMatcher
- $match : AbstractMatch
blockableStringExpression()
Allows to modify the passed string expression to a blockable.
public
blockableStringExpression(string $expression, AbstractBlockable $blockable) : string
Parameters
- $expression : string
- $blockable : AbstractBlockable
Return values
stringblockedMatch()
See `AbstractPlugin`.
public
blockedMatch(BlockedResult $result, AbstractMatcher $matcher, AbstractMatch $match) : mixed
Parameters
- $result : BlockedResult
- $matcher : AbstractMatcher
- $match : AbstractMatch
checkResult()
Special case: Read attribute of the original embed URL if it got passed via a custom attribute.
public
checkResult(BlockedResult $result, AbstractMatcher $matcher, AbstractMatch $match) : BlockedResult
Parameters
- $result : BlockedResult
- $matcher : AbstractMatcher
- $match : AbstractMatch
Return values
BlockedResultfetchMetadata()
Use multiple mechanism to extract a thumbnail from any URL. It returns an map of URL => thumbnail, and if a thumbnail got not found it is no longer part of the returned map.
public
fetchMetadata(array<string|int, Thumbnail> &$thumbnails) : mixed
Mechanism:
- Cache
- Oembed
- HTML Head Parser and extract thumbnail URL from known meta tags
Parameters
- $thumbnails : array<string|int, Thumbnail>
-
Key needs to be the embed URL
getCache()
Getter.
public
getCache() : mixed
Tags
getHeadlessContentBlocker()
Getter.
public
final getHeadlessContentBlocker() : mixed
Tags
getWriteJson()
Create the result for the HTML attribute which our unblocker can consume.
public
getWriteJson(Thumbnail $thumbnail) : mixed
Parameters
- $thumbnail : Thumbnail
init()
Init.
public
init() : mixed
inlineStyleBlockRule()
Decide if a URL in a CSS rule should be blocked.
public
inlineStyleBlockRule(BlockedResult $result, string $url, StyleInlineMatcher|StyleInlineAttributeMatcher $matcher, StyleInlineMatch|StyleInlineAttributeMatch $match) : bool
Parameters
- $result : BlockedResult
- $url : string
- $matcher : StyleInlineMatcher|StyleInlineAttributeMatcher
- $match : StyleInlineMatch|StyleInlineAttributeMatch
Return values
boolinlineStyleModifyDocuments()
Allows to modify blocked CSS documents.
public
inlineStyleModifyDocuments(Document $document, Document $extractedDocument, StyleInlineMatcher|StyleInlineAttributeMatcher $matcher, StyleInlineMatch|StyleInlineAttributeMatch $match) : bool
Parameters
- $document : Document
- $extractedDocument : Document
- $matcher : StyleInlineMatcher|StyleInlineAttributeMatcher
- $match : StyleInlineMatch|StyleInlineAttributeMatch
Return values
boolinlineStyleShouldBeExtracted()
Do not extract blocked rules of a CSS inline script to a second document.
public
inlineStyleShouldBeExtracted(bool $extract, StyleInlineMatcher|StyleInlineAttributeMatcher $matcher, StyleInlineMatch|StyleInlineAttributeMatch $match) : bool
Parameters
- $extract : bool
- $matcher : StyleInlineMatcher|StyleInlineAttributeMatcher
- $match : StyleInlineMatch|StyleInlineAttributeMatch
Return values
boolkeepAlwaysAttributes()
Keep attributes for a specific match.
public
keepAlwaysAttributes(array<string|int, string> $keepAttributes, AbstractMatcher $matcher, AbstractMatch $match) : array<string|int, string>
Parameters
- $keepAttributes : array<string|int, string>
- $matcher : AbstractMatcher
- $match : AbstractMatch
Return values
array<string|int, string>modifyHtmlAfterProcessing()
Allows to modify the HTML after the content blocker has done its job.
public
modifyHtmlAfterProcessing(string $html) : mixed
Parameters
- $html : string
notBlockedMatch()
Called after a match got not blocked. Opposite of `blockedMatch`.
public
notBlockedMatch(BlockedResult $result, AbstractMatcher $matcher, AbstractMatch $match) : mixed
Parameters
- $result : BlockedResult
- $matcher : AbstractMatcher
- $match : AbstractMatch
revertTransformAttributeOnMatch()
When a match with `consent-thumbnail is found, revert the transformation of the attribute.
public
revertTransformAttributeOnMatch(AbstractMatch $match) : mixed
Parameters
- $match : AbstractMatch
setCache()
Setter.
public
setCache(ImagePreviewCache $cache) : mixed
Parameters
- $cache : ImagePreviewCache
Tags
setup()
Before the content blocker gets setup.
public
setup() : mixed
skipInlineScriptVariableAssignment()
Skip inline script by variable name.
public
skipInlineScriptVariableAssignment(array<string|int, string> $names, ScriptInlineMatcher $matcher, ScriptInlineMatch $match) : array<string|int, string>
Parameters
- $names : array<string|int, string>
- $matcher : ScriptInlineMatcher
- $match : ScriptInlineMatch
Return values
array<string|int, string>visualParent()
Set a visual parent for a specific match.
public
visualParent(bool|string|number $visualParent, AbstractMatcher $matcher, AbstractMatch $match) : bool|string|number
Parameters
- $visualParent : bool|string|number
- $matcher : AbstractMatcher
- $match : AbstractMatch
Return values
bool|string|numberfindUrlForSpecialMatch()
Find an embed URL for a special match.
protected
findUrlForSpecialMatch(AbstractMatch $match) : mixed
Parameters
- $match : AbstractMatch
isValidEmbedUrl()
Check if a given embed URL is valid.
protected
isValidEmbedUrl(string $embedUrl[, bool $respectSpecialCases = true ]) : mixed
Parameters
- $embedUrl : string
- $respectSpecialCases : bool = true
revertTransformAttribute()
Revert the transformation of a URL attribute when we have found a thumbnail and it is cached.
protected
revertTransformAttribute(string $html) : mixed
Parameters
- $html : string