A wasmCloud Actor for converting images to webp format and optionally resizing them. This is purely for my own personal use, but could be used by others or as a template for other kinds of image manipulation
Once this actor is exposed via a wasmcloud:httpserver implementation, it is fairly straightforward
to use. It is a POST request to the URL (an example is below):
$ curl -X POST -H 'Content-Type: image/jpeg' -v 'http://127.0.0.1:8080' --data-binary @/path/to/your/picture --output test.webp
The actor can handle most of the common image types such as PNG, JPEG, GIF, PNG, and TIFF. You can set your content-type accordingly (or omit it if your hosting provider lets you, it definitely works without it locally).
If you want to resize the image, the longest_side_pixels query string parameter can be passed. If
the number of pixels exceeds the current size, it will be ignored. It will also be ignored if a
number is not passed.
$ curl -X POST -H 'Content-Type: image/jpeg' -v 'http://127.0.0.1:8080?longest_side_pixels=1024' --data-binary @/path/to/your/picture --output test.webp
For smaller pictures, all of the default settings should work great. However, if you are processing larger pictures, you'll probably want to bump up some timeout values (as a wasmCloud maintainer, I know we are thinking of making this a little less painful):
When you start your wasmCloud Host, set WASMCLOUD_RPC_TIMEOUT_MS to a higher value like 15000.
And then, when you add your link definition to the http server, use the following config:
$ echo -n '{"address": "0.0.0.0:8080", "timeout_ms": 15000}' | base64
eyJhZGRyZXNzIjogIjAuMC4wLjA6ODA4MCIsICJ0aW1lb3V0X21zIjogMTUwMDB9
Then in the linkdef, set
config_b64=eyJhZGRyZXNzIjogIjAuMC4wLjA6ODA4MCIsICJ0aW1lb3V0X21zIjogMTUwMDB9.
Besides a normal Rust build toolchain, you'll also need to have libwebp available. Instructions
can be found here to install it.
Additionally, you need to have the wasi-sdk available in order to compile everything for webp correctly. You can find the latest releases here. Once you download the proper tarball from the release, you can run the following steps:
# Replace with the correct tarball name for you
$ tar xzvf wasi-sdk-17.0-macos.tar.gz
# Now export some vars to make sure you can build, replacing with your directory location
export PATH="<path to wasi-sdk dir>/bin:${PATH}"
export TARGET_CFLAGS='-I <path to wasi-sdk dir>/share/wasi-sysroot/include/'
export CC='<path to wasi-sdk dir>/bin/clang'
Once that is in place, you can just call wash build to actually build it
NOTE: I couldn't get VSCode to build for me just by setting these vars. So I had to do ye-olde-run-a-terminal-command to check for some of the compilation errors