dendrite/mediaapi
Kiril Vladimiroff d5dbe546e4
Always defer *sql.Rows.Close and consult with Err (#844)
* Always defer *sql.Rows.Close and consult with Err

database/sql.Rows.Next() makes sure to call Close only after exhausting
result rows which would NOT happen when returning early from a bad Scan.
Close being idempotent makes it a great candidate to get always deferred
regardless of what happens later on the result set.

This change also makes sure call Err() after exhausting Next() and
propagate non-nil results from it as the documentation advises.

Closes #764

Signed-off-by: Kiril Vladimiroff <kiril@vladimiroff.org>

* Override named result parameters in last returns

Signed-off-by: Kiril Vladimiroff <kiril@vladimiroff.org>

* Do the same over new changes that got merged

Signed-off-by: Kiril Vladimiroff <kiril@vladimiroff.org>

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
2020-02-11 14:12:21 +00:00
..
fileutils use go module for dependencies (#594) 2019-05-21 21:56:55 +01:00
routing Implement storage interfaces (#841) 2020-01-03 14:07:05 +00:00
storage Always defer *sql.Rows.Close and consult with Err (#844) 2020-02-11 14:12:21 +00:00
thumbnailer Implement storage interfaces (#841) 2020-01-03 14:07:05 +00:00
types use go module for dependencies (#594) 2019-05-21 21:56:55 +01:00
bimg-96x96-crop.jpg use go module for dependencies (#594) 2019-05-21 21:56:55 +01:00
mediaapi.go use go module for dependencies (#594) 2019-05-21 21:56:55 +01:00
nfnt-96x96-crop.jpg use go module for dependencies (#594) 2019-05-21 21:56:55 +01:00
README.md Update Docker files and remove references to gb (#703) 2019-05-22 10:44:25 +01:00

Media API

This server is responsible for serving /media requests as per:

http://matrix.org/docs/spec/client_server/r0.2.0.html#id43

Scaling libraries

nfnt/resize (default)

Thumbnailing uses https://github.com/nfnt/resize by default which is a pure golang image scaling library relying on image codecs from the standard library. It is ISC-licensed.

It is multi-threaded and uses Lanczos3 so produces sharp images. Using Lanczos3 all the way makes it slower than some other approaches like bimg. (~845ms in total for pre-generating 32x32-crop, 96x96-crop, 320x240-scale, 640x480-scale and 800x600-scale from a given JPEG image on a given machine.)

See the sample below for image quality with nfnt/resize:

bimg (uses libvips C library)

Alternatively one can use go build -tags bimg to use bimg from https://github.com/h2non/bimg (MIT-licensed) which uses libvips from https://github.com/jcupitt/libvips (LGPL v2.1+ -licensed). libvips is a C library and must be installed/built separately. See the github page for details. Also note that libvips in turn has dependencies with a selection of FOSS licenses.

bimg and libvips have significantly better performance than nfnt/resize but produce slightly less-sharp images. bimg uses a box filter for downscaling to within about 200% of the target scale and then uses Lanczos3 for the last bit. This is a much faster approach but comes at the expense of sharpness. (~295ms in total for pre-generating 32x32-crop, 96x96-crop, 320x240-scale, 640x480-scale and 800x600-scale from a given JPEG image on a given machine.)

See the sample below for image quality with bimg: