mirror of https://github.com/AMT-Cheif/drift.git
58 lines
2.3 KiB
Dart
58 lines
2.3 KiB
Dart
/// Experimental bindings to the [json1](https://www.sqlite.org/json1.html)
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/// sqlite extension.
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///
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/// Note that the json1 extension might not be available on all runtimes. In
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/// particular, it can only work reliably on Android when using the
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/// [moor_ffi](https://moor.simonbinder.eu/docs/other-engines/vm/) and it might
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/// not work on older iOS versions.
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@experimental
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library json1;
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import 'package:meta/meta.dart';
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import '../moor.dart';
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/// Defines extensions on string expressions to support the json1 api from Dart.
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extension JsonExtensions on Expression<String, StringType> {
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/// Assuming that this string is a json array, returns the length of this json
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/// array.
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///
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/// The [path] parameter is optional. If it's set, it must refer to a valid
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/// path in this json that will be used instead of `this`. See the
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/// [sqlite documentation](https://www.sqlite.org/json1.html#path_arguments)
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/// for details. If [path] is an invalid path, this expression can cause an
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/// error when run by sqlite.
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///
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/// For this method to be valid, `this` must be a string representing a valid
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/// json array. Otherwise, sqlite will report an error when attempting to
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/// evaluate this expression.
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///
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/// See also:
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/// - the [sqlite documentation for this function](https://www.sqlite.org/json1.html#the_json_array_length_function)
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Expression<int, IntType> jsonArrayLength([String path]) {
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return FunctionCallExpression('json_array_length', [
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this,
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if (path != null) Variable.withString(path),
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]);
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}
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/// Assuming that this string is a json object or array, extracts a part of
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/// this structure identified by [path].
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///
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/// For more details on how to format the [path] argument, see the
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/// [sqlite documentation](https://www.sqlite.org/json1.html#path_arguments).
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///
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/// Evaluating this expression will cause an error if [path] has an invalid
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/// format or `this` isn't well-formatted json.
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///
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/// Note that, since the return type of this function is dynamic, it can't be
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/// used in [JoinedSelectStatement.addColumns]. It's also recommended to use
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/// [Expression.equalsExp] with an explicit [Variable] instead of
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/// [Expression.equals].
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Expression jsonExtract(String path) {
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return FunctionCallExpression('json_extract', [
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this,
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Variable.withString(path),
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]);
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}
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}
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