A drop-in, lightweight replacement for "data:" Uri.
Example:
final dataUri = parseUri('data:audio/mpeg;base64,....');
print(dataUri.runtimeType); // SlimDataUri
final uri = parseUri('http://www.google.com');
print(uri.runtimeType); // UriThis package provides function Uri parseUri(String uri) as a replacement to Dart's Uri.parse(String uri). It returns an instance of SlimDataUri for URIs with a data: scheme, and falls back to Dart's Uri.parse() for other schemes.
Contrary to Dart's Uri implementation, SlimDataUri does not parse the data payload, thus yielding much better performance for large data payloads.
The example folder provides a benchmark:
dart run example/main.dart
Sample output (base64 benchmark):
[Uri parsing] #0: initializing 16777216 bytes...
[Uri parsing] #0: dry run...
[Uri parsing] #1: initializing 16777216 bytes...
[Uri parsing] * Dart Uri: 0:00:00.215011
[Uri parsing] * SlimDataUri: 0:00:00.000016
[Uri parsing] #2: initializing 17825792 bytes...
[Uri parsing] * Dart Uri: 0:00:00.167898
[Uri parsing] * SlimDataUri: 0:00:00.000015
[Uri parsing] #3: initializing 23068672 bytes...
[Uri parsing] * Dart Uri: 0:00:00.280060
[Uri parsing] * SlimDataUri: 0:00:00.000013
[Uri parsing] #4: initializing 16777216 bytes...
[Uri parsing] * Dart Uri: 0:00:00.138297
[Uri parsing] * SlimDataUri: 0:00:00.000009
Uri parsing - GRAND TOTAL:
* Total bytes = 74448896
* Dart Uri = 0:00:00.801266 --> 0.091 KiB/µs
* SlimDataUri = 0:00:00.000053 --> 1371.774 KiB/µs
* ratio = Infinity
[Byte content] #0: initializing 16777216 bytes...
[Byte content] #0: dry run...
[Byte content] #1: initializing 22020096 bytes...
[Byte content] * Dart Uri: 0:00:00.313630
[Byte content] * SlimDataUri: 0:00:00.129395
[Byte content] #2: initializing 23068672 bytes...
[Byte content] * Dart Uri: 0:00:00.348454
[Byte content] * SlimDataUri: 0:00:00.152085
[Byte content] #3: initializing 18874368 bytes...
[Byte content] * Dart Uri: 0:00:00.258945
[Byte content] * SlimDataUri: 0:00:00.114646
[Byte content] #4: initializing 19922944 bytes...
[Byte content] * Dart Uri: 0:00:00.334124
[Byte content] * SlimDataUri: 0:00:00.125372
Byte content - GRAND TOTAL:
* Total bytes = 83886080
* Dart Uri = 0:00:01.255153 --> 0.065 KiB/µs
* SlimDataUri = 0:00:00.521498 --> 0.157 KiB/µs
* ratio = 2.409
Because SlimDataUri does not parse the data payload, any input provided to parseUri or SlimDataUri.parse, SlimDataUri.base64 or SlimDataUri.percent must be checked and sanitized beforehand. Failure to do so may result in malicious users providing invalid data that has ben crafted to conduct eg. Cross-Site Scripting (XSS) attacks. For instance, if your program receives base64 or percent-encoded data, it should check that the input is well-formed before using SlimDataUri. Alternatively, user input can be systematically base64 or percent-encoded by your code to guarantee safety.
To circumvent security issues, parseUri, SlimDataUri.parse, SlimDataUri.base64 and SlimDataUri.percent support an optional safetyCheck parameter (default value false) to check data content and make sure it does not contain forbidden characters such as " or ' that could be used in XSS attacks, at the price of performance. Invalid characters will cause parsing to throw an exception.
SlimDataUri also provides a boolean isSafeContent property which can then be checked "just-in-time", for instance before integrating the data: Uri into some HTML content. This property does not throw but returns false if the data contains any invalid character. Please note that it may return true even if the content is invalid: for instance, %% is invalid percent-encoded data and A=B is invalid base64 content, yet SlimDataUri.isSafeContent will return true because payloads contain safe characters. Under such circumstances, parsing will succeed and SlimDataUri.isSafeContent will return true, but SlimDataUri.contentAsByte() will throw when trying to decode the payload.