正则表达式模式匹配电子邮件内联回复标题

Question

I'm having a little trouble figuring out the pattern to identify the beginning of inline replies/forwards in an email body, there are some easier ones that simply begin with something like "Begin forwarded message" but the replies are a little more complicated:

On 12-06-13 10:56 AM, "John Doe" <john.doe@some.tld> wrote:

Obviously the constants will be "On" and "wrote:". I'd like to be able to find only the first match and then either wrap everything after it in a div with display:none applied or even just eliminate it using substr($body,0, POSITION_OF_MATCH).

One of the issues I'm having is that it's not catching the FIRST occurrence, and second is that I can't get the greediness to work properly.

My progress (having fallen back to at least a partially working version) so far is:

preg_match("/On [^>]* wrote:/i",$content,$matches,PREG_OFFSET_CAPTURE);

Any help would be greatly appreciated!

Answer 1

I wonder how your current version works at all, because you cannot possibly match the closing > . But you could do something like this:

$content = preg_replace('/(On [^>]*> wrote:).*$/s', '$1', $content);

Which will match the first On ... wrote: and everything after that up until the end of the string. And replace it by just the On ... wrote: .

Answer 2

You can probably break this down by elements; so you basically have:

On DATE, "NAME" <EMAIL> wrote:

You can then characterize DATE , NAME , and EMAIL .

• DATE is composed of numbers, dashes, spaces, colons, and letters. However, it ends with a comma, so you can use that instead.
• NAME is composed of letters and spaces, though it is delimited by quotes, and you can probably handle that.
• EMAIL is a bit more complicated, but emails cannot contain the character > , so you should be able to capture everything but that.

So you basically get:

On [anything but comma], "[anything but "]" <[anything but >]> wrote:

Which, in regex, is something like:

/^On ([^,]+), \"([^\"]+)\" <([^>]+)> wrote:$/

Then, when using preg_match , you can get your matches from some $matches array, indices 1 through 3.

Answer 3

I suggest

$email = preg_match('/^On [^"]*"[^"]*" <([^>]*)> wrote:$/', $str, $re) ? $re[1] : '';

See this demo .

Answer 4

I appreciate the other answers, but none of them really took into account the many possible variations in the reply strings I was dealing with, that might have been my fault for not explaining properly or providing more options. I've +1'd everyone for their efforts though.

The final solution which seems to be working best after a day of fiddling with it on and off is this:

/On (Mon|Tue|Wed|Thu|Fri|Sat|Sun|[[:digit:]]{1,2})(.*?) wrote:/i

The option list that it begins with covers a range of different reply types that start with "On Tue..." or "On 23..." or "On 1...", etc. ensuring that the greediness I was complaining about wasn't taking in too much from random "on" strings elsewhere, the (.*?) takes care of the rest of the name/email portion, finally following up with "wrote:" to finish it off.