oleibman
9b122cd028
The native preg functions (preg_match, preg_replace, etc.) often require us to add a lot of useless boilerplate code to satisfy Phpstan, Scrutinizer, etc. Composer/Pcre offers us a way to remove that boilerplate, thereby giving us a cleaner codebase. I decided to try it on a few modules, and saw a result that clearly demonstrated the usefulness of doing this (aside from the cleaner codebase). Sample 22_Reader_issue1767 reads an Xlsx spreadsheet with complex sheet names used in defined names, and writes it to Xlsx and Xls output files. When I changed Writer/Xls/Parser to use Composer/Pcre, this sample failed in many different places writing the Xls file. It turns out that some regexes were failing not because the string didn't match, but because the regex encountered "catastrophic backtracing". Composer/Pcre throws an exception when this happens; the native preg_match does return false, but we were not checking for that. The regexes in question are now changed to something which works, and formal unit tests are added for them. Finding this previously undetected error indicates that we should proceed with this change. An alternative to using Composer/Pcre would be to test for false after all the preg calls. I have done this in the two samples changed with this PR. That seems adequate for a small number of changes, but it really just makes for more clutter considering the large number of regexps that we use in our code. I think Composer/Pcre is a better choice. It isn't quite transparent. Composer forces all regexps to use PREG_UNMATCHED_AS_NULL, so some match fields will now be null instead of null-string (or non-existent if the unmatched field comes at the end). Our test suite doesn't report any problem (yet) due to this change, although Phpstan is sensitive to it. Several Phpstan annotations were eliminated due to this change, but some others are now needed. It is not necessary to do this all at once. This PR addresses all the calls in Writer. I intend to address other components in several tickets.
PhpSpreadsheet
PhpSpreadsheet is a library written in pure PHP and offers a set of classes that allow you to read and write various spreadsheet file formats such as Excel and LibreOffice Calc.
Installation
See the install instructions.
Documentation
Read more about it, including install instructions, in the official documentation. Or check out the API documentation.
Please ask your support questions on StackOverflow, or have a quick chat on Gitter.
Patreon
I am now running a Patreon to support the work that I do on PhpSpreadsheet.
Supporters will receive access to articles about working with PhpSpreadsheet, and how to use some of its more advanced features.
Posts already available to Patreon supporters:
- The Dating Game
- A look at how MS Excel (and PhpSpreadsheet) handle date and time values.
- Looping the Loop
- Advice on Iterating through the rows and cells in a worksheet.
And for Patrons at levels actively using PhpSpreadsheet:
- Behind the Mask
- A look at Number Format Masks.
The Next Article (currently Work in Progress):
- Formula for Success
- How to debug formulae that don't produce the expected result.
My aim is to post at least one article each month, taking a detailed look at some feature of MS Excel and how to use that feature in PhpSpreadsheet, or on how to perform different activities in PhpSpreadsheet.
Planned posts for the future include topics like:
- Tables
- Structured References
- AutoFiltering
- Array Formulae
- Conditional Formatting
- Data Validation
- Value Binders
- Images
- Charts
After a period of six months exclusive to Patreon supporters, articles will be incorporated into the public documentation for the library.
PHPExcel vs PhpSpreadsheet ?
PhpSpreadsheet is the next version of PHPExcel. It breaks compatibility to dramatically improve the code base quality (namespaces, PSR compliance, use of latest PHP language features, etc.).
Because all efforts have shifted to PhpSpreadsheet, PHPExcel will no longer be maintained. All contributions for PHPExcel, patches and new features, should target PhpSpreadsheet master branch.
Do you need to migrate? There is an automated tool for that.
License
PhpSpreadsheet is licensed under MIT.