RegEx in use with an InboundEmail.htmlBody String is not matching a Pattern

Question

Apologies for the poor formatting; first time poster.

I'm working with an InboundEmail object being sent it from a form from one of our internal systems - it's basically just sending an HTML email into Salesforce. We want to get the answers that have been provided on the form, and RegEx is the way we're trying to do it. Here's a snippit of the HTML coming into Salesforce:

                        <td><img src="/images/spacer.gif" width="10" height="1"></td>
                        <td><span style="color:;"><b>Description of Incident</b></span></td>
                    </tr>

                    <tr>
                        <td colspan="3"><img src="/images/spacer.gif" width="1" height="5"></td>
                    </tr>
                    <tr>                
                        <td colspan="2"><img src="/images/spacer.gif" width="10" height="1"></td>
                        <td style="width:100%">The incident failed for no good reason.</td>
                    </tr>
                    <tr>
                        <td colspan="3"><img src="/images/spacer.gif" width="1" height="15"></td>
                    </tr>

In the above example, the question is Description of incident and the answer is The incident failed for no good reason. So the RegEx pattern we're using is the following:

Desc((.|\n)?)%.

This will get us everything from the word Desc right up to the tag beside the answer. I've tested this in RegEx builders and can confirm this is the case.

So here's the APEX code I'm using in Salesforce, this gets triggered when an email is sent into SF:

String descriptionRegex = 'Desc((.|\n)?)%.'; String extracteddescription = ''; String finaldescription = ''; Pattern descriptionPattern = Pattern.compile(descriptionRegex); Matcher descriptionMatcher = descriptionPattern.matcher(email.htmlBody);

if (descriptionMatcher.matches()) {

System.debug('Found a match'); extractedDescription = descriptionMatcher.group(0); System.debug('Group extract: ' + extracteddescription); System.debug('index of percentage: ' + extracteddescription.indexOf('%')); System.debug('index of less than: ' + wxtracteddescription.lastIndexOf('<'));

finaldescription = extracteddescription.substring((extracteddescription.indexOf('%') + 3), extracteddescription.lastIndexOf('<')); System.debug('Final description: ' + finaldescription); } else { System.debug('Did not find a match'); }

Expected result

With the above code, I'm getting the block of text (previously confirmed that I should be returning using the above Pattern), if I've found a match, then extract the answer using a String.substring method.

Actual result

When the code runs, I hit the else condition, and no pattern is matched.

Any idea why my code isn't working?

Also some supplementary information; the htmlBody variable is returning the HTML of the email. I've put said variable result into a debug statement, and ran the output HTML against my RegEx and can confirm it should be picked up

Answer 1

Don't worry, you've got 100 problems now.

I had a problem with regex's where there were multiple lines for the regex to parse.

For example, I have two strings:

1. 'hello'
2. '123\nhello'

Matching .*ell.* will come back fine on the first string, but not the second.

Meet single line and multi line modifers: (?ms)

(?ms).*ell.* will now match on that second string.

Proof:

Try doing this in developer console, and check the output:

String input = '123\nhello';
Pattern p1 = Pattern.compile('.*ell.*');
Pattern p2 = Pattern.compile('(?ms).*ell.*');
system.debug(p1.matcher(input).matches());
system.debug(p2.matcher(input).matches());

Answer 2

In the end we used a different method in order to get at the data we wanted, we used the find() (link) which returned the results that we expected. Before we were trying to use match() (link) which tries to match the pattern against the entire string - I'm still pretty sure what we were trying to do falls under this remit however.

As recommended by Salesforce Support to us, the find() method attempts to find the next subsequence of the input sequence that matches the pattern. This method returns true if a subsequence of the input sequence matches this Matcher object's pattern. which does seem more specific to our case.

Thank you for your help on this.