正则表达式Youtube - 除了特定的视频哈希外，将自动播放设置为0

Question

I want to remove all references to autoplay in an URL - even multiple times if they exist - for all videos except the one (Uj1ykZWtPYI). The other settings URL parameters should remain.

Source: 
<iframe src="//www.youtube.com/embed/1337?wmode=transparent&autoplay=1&controls=0&showinfo=0&modestbranding=1" frameborder="0" allowfullscreen=""></iframe>

Desired:
<iframe src="//www.youtube.com/embed/1337?wmode=transparent&controls=0&showinfo=0&modestbranding=1&autoplay=0" frameborder="0" allowfullscreen=""></iframe>

It appends autoplay=0 programmatically.

---

For the specified video (Uj1ykZWtPYI), it should behave like this:

Source: 
<iframe src="//www.youtube.com/embed/Uj1ykZWtPYI?wmode=transparent&autoplay=0&controls=0&showinfo=0&modestbranding=1" frameborder="0" allowfullscreen=""></iframe>

Desired:
<iframe src="//www.youtube.com/embed/Uj1ykZWtPYI?wmode=transparent&controls=0&showinfo=0&modestbranding=1&autoplay=1" frameborder="0" allowfullscreen=""></iframe>`

It appends autoplay=1 programmatically.

---

What I've tried so far in PHP:

// Non-matching specific video
$content['message'] = preg_replace('/youtube.com\/embed\/([^Uj1ykZWtPYI]*)([^"&]*)/', 'youtube.com/embed/$1$2&autoplay=0', $content['message']);

// Result
// <iframe src="//www.youtube.com/embed/W6hr-o6JiWs?wmode=transparent&autoplay=1&autoplay=0" frameborder="0" allowfullscreen="">

// Matching specific video
$content['message'] = preg_replace('/youtube.com\/embed\/([Uj1ykZWtPYI]*)([^"&]*)/', 'youtube.com/embed/$1$2&autoplay=1', $content['message']);

// Result
// <iframe src="//www.youtube.com/embed/Uj1ykZWtPYI?wmode=transparent&autoplay=1&autoplay=0&controls=0&showinfo=0&modestbranding=1" frameborder="0" allowfullscreen=""></iframe>

Answer 1

Matching all links without Uj1ykZWtPYI

You can search for this regular expression to find all matches without Uj1ykZWtPYI in the URL:

\b(src="(?:(?!Uj1ykZWtPYI|").)+?)(?:&autoplay=(?:1|0))([^"]*?)"|\b(src="(?:(?!Uj1ykZWtPYI|"|&autoplay=(?:1|0)).)+?)"

Then, replace the it with this (autoplay is zero):

$1$2$3&autoplay=0"

---

Explanation:

• \b(src="(?:(?!Uj1ykZWtPYI|").)+?)(?:&autoplay=(?:1|0))([^"]*?)": The first part of the pattern looks for any characters after src=", which are not equal an apostrophe [^"] or !Uj1ykZWtPYI and stops at autoplay. This forms the first group. The pattern has to have the characters &autoplay=1 or &autoplay=0 in it. After autoplay, everything except the " character is included into the second group - until ".
• \b(src="(?:(?!Uj1ykZWtPYI|"|&autoplay=(?:1|0)).)+?)": The second part matches any url without an autoplay, a " and Uj1ykZWtPYI in it, but otherwise is the same as the first pattern.
• If pattern 1 matches, the groups $1 and $2 form the valid URL without autosave. If it does not match, but the second one does, $3 will contain the full URL. So, $1$2$3 depicts in any of the two cases the full URL. &autoplay=0 is then added to the full URL afterwards.

This pattern only works, if autoplay is not the first argument (?autoplay).

---

Matching all links including the video code Uj1ykZWtPYI

If you want to match every link with Uj1ykZWtPYI in it to add autoplay=1 you can use a pretty similar pattern:

\b(src="[^"]*?Uj1ykZWtPYI[^"]*?)(?:&autoplay=(?:1|0))([^"]*?)"|\b(src="[^"]*?Uj1ykZWtPYI(?:(?!&autoplay=(?:1|0))[^"])+?)"

Then replace it with this (autoplay is one):

$1$2$3&autoplay=1"

---

Live Example

Here you can see both patterns in action (JavaScript) to replace your example string (all four example string combinations are added):

// 1337 as code, including autoplay
var string1 = '<iframe src="//www.youtube.com/embed/1337?wmode=transparent&autoplay=1&controls=0&showinfo=0&modestbranding=1" frameborder="0" allowfullscreen=""></iframe>';
// Uj1ykZWtPYI as code, including autoplay
var string2 = '<iframe src="//www.youtube.com/embed/Uj1ykZWtPYI?wmode=transparent&autoplay=1&controls=0&showinfo=0&modestbranding=1" frameborder="0" allowfullscreen=""></iframe>';
// 1337 as code, autoplay not included
var string3 = '<iframe src="//www.youtube.com/embed/1337?wmode=transparent&controls=0&showinfo=0&modestbranding=1" frameborder="0" allowfullscreen=""></iframe>';
// Uj1ykZWtPYIas code, autoplay not included
var string4 = '<iframe src="//www.youtube.com/embed/Uj1ykZWtPYI?wmode=transparent&controls=0&showinfo=0&modestbranding=1" frameborder="0" allowfullscreen=""></iframe>';

var regex1 = /\b(src="(?:(?!Uj1ykZWtPYI|").)+?)(?:&autoplay=(?:1|0))([^"]*?)"|\b(src="(?:(?!Uj1ykZWtPYI|"|&autoplay=(?:1|0)).)+?)"/g;
var regex2 = /\b(src="[^"]*?Uj1ykZWtPYI[^"]*?)(?:&autoplay=(?:1|0))([^"]*?)"|\b(src="[^"]*?Uj1ykZWtPYI(?:(?!&autoplay=(?:1|0))[^"])+?)"/g;
var replacement1 = '$1$2$3&autoplay=0"';
var replacement2 = '$1$2$3&autoplay=1"';

console.log(string1.replace(regex1, replacement1));
console.log(string2.replace(regex2, replacement2));
console.log(string3.replace(regex1, replacement1));
console.log(string4.replace(regex2, replacement2));

</div>