JIRA ticket: LIMS-1275

Summary:

Large files can cause the server to run out of memory. Use a streamed response instead of loading the whole file into memory when unzipping.

Changes:

• Don't set a memory limit as that was a bandaid
• Don't set the content length header as Symfony deals with that automatically
• Unzip and send 8kb of the file at a time, flushing from PHP's buffer and from the web server's buffer each time

To test:

• Go to any data collection with an AutoProc result (eg /dc/visit/cm40607-5/id/20430060)
• Click the Logs & Files button, then find the summary_inlined.html file, this is usually pretty large
• Check the View button loads the file into a frame, and the Download button loads the file into the browser tab
• Zip the file, keeping but renaming the original (to preserve permissions), and check it now downloads the zipped file, then undo the renaming after, eg

gzip -k summary_inlined.html
mv summary_inlined.html summary_inlined.original
# test Synchweb still works as expected
mv summary_inlined.original summary_inlined.html
rm summary_inlined.html.gz

• Check the downloaded zipped file is valid and contains the expected file