I am using a library to read XLS files which internally uses PHP's zip_open() function. When creating the files locally and then uploading to my test server everything works fine. However, when I use the XLS files downloaded from a website (normal download via browser), it does not work, instead returning Error 19 meaning that the file is not seen as a zip file, which is incorrect. Excel opens the file without problems. If I re-save the file locally as an XLSX file and then upload it, I get the same error (in this instance the file is opened by the PHP's ZipArchive class). Any ideas what the reason could be? I checked that the files are not read only, possibly some Unix permissions could be set that are not displayed in Windows? (Doubt this, as the error code indicates that the file could be accessed, but could not be identified as XLS)
Using:
Apache under Windows (WAMP)
PHP 5.4.12
It seems I had misread a line of code, the zip check is only done to determine if the XLS file is an incorrectly named XLSX file. The problem with the XLS file is that it returns no sheets when parsing, I need to look into this still. I do not know why saving the XLS file as an XLSX file (using Excel) results in an incorrect ZIP archive though, but guessing it is related.