If display_errors is on, typical settings would cause PHP error messages to spew to output before the HTTP headers for setting a 400 error go through.
Also switched from deprecated static DOMDocument::loadXML() to non-static call.
Was triggering errors due to use of common_canonical_nickname() on arbitrary input without checking for exceptions about invalid nicknames (which didn't exist long ago in the before time)
As a hack this removes the mysql_timestamp bit from the field settings on reply.modified so that our value actually gets saved. This *should* work ok as long as system timezone is set correctly, which we now set to UTC to match when connecting.
UserActivityStream -- used to create a full activity stream including subscriptions, favorites, notices, etc -- normally buffers everything into memory at once. This is infeasible for accounts with long histories of serious usage; it can take tens of seconds just to pull all records from the database, and working with them all in memory is very likely to hit resource limits.
This commit adds an alternate mode for this class which avoids pulling notices until during the actual output. Instead of pre-sorting and buffering all the notices, empty spaces between the other activities are filled in with notices as we're making output. This means more smaller queries spread out during operations, and less stuff kept in memory.
Callers (backupaccount action, and backupuser.php) which can stream their output pass an $outputMode param of UserActivityStream::OUTPUT_RAW, and during getString() it'll send straight to output as well as slurping the notices in this extra funky fashion.
Other callers will let it default to the OUTPUT_STRING mode, which keeps the previous behavior.
There should be a better way to do this, swapping out the stringer output for raw output more consitently.
Changes the replacement of Twitter "entities" from in-place reverse ordering ('to preserve indices') to a forward-facing append-in-chunks that pulls in both the text and link portions, and escapes them all.
This unfortunately means first *de*-escaping the < and > that Twitter helpfully adds for us.... and any literal &blah;s that get written. This seems to match Twitter's web UI, however horrid it is.
