riverflow

Description:

riverflow

A library for Dart developers.
Usage #

Create a Template


import 'dart:convert';

import 'package:http/http.dart' as http;
import 'package:riverflow/riverflow.dart';

final stage1 = DomStage(
inputMapping: {
'package_html': '/_body',
},
outputFields: {
'package_html': FieldSelector(
extractors: [
HtmlIncludeExtractor(
selector: 'div[class="packages"] div[class="packages-item"]',
)
],
isFlatten: true,
collectAs: DefaultCollector(CollectTypes.ARRAY, OutputTypes.HTML_ELEMENT, null),
),
},
excludeMapping: {
'/_body',
},
);
final stage2 = DomStage(
inputMapping: {
'package_name': '/package_html',
'description': '/package_html',
'likes': '/package_html',
'health': '/package_html',
'popularity': '/package_html',
},
outputFields: {
'package_name': FieldSelector(
extractors: [
HtmlExtractor(selector: 'h3[class="packages-title"]', collectors: [r'${text()}']),
StringTrimExtractor(),
],
),
'description': FieldSelector(
extractors: [
HtmlExtractor(selector: 'p[class="packages-description"]', collectors: [r'${text()}'])
],
),
'likes': FieldSelector(
extractors: [
HtmlExtractor(
selector: 'div[class*="packages-score-like"] *[class="packages-score-value-number"]',
collectors: [r'${text()}'])
],
collectAs: DefaultCollector(CollectTypes.FIRST, OutputTypes.INT, 0),
),
'health': FieldSelector(
extractors: [
HtmlExtractor(
selector: 'div[class*="packages-score-health"] *[class="packages-score-value-number"]',
collectors: [r'${text()}']),
],
collectAs: DefaultCollector(CollectTypes.FIRST, OutputTypes.INT, 0),
),
'popularity': FieldSelector(
extractors: [
HtmlExtractor(
selector: 'div[class*="packages-score-popularity"] *[class="packages-score-value-number"]',
collectors: [r'${text()}']),
],
),
},
excludeMapping: {
'/package_html',
},
);

final template = Template([stage1, stage2]);
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Or Create a Template from a Json String

final template = Template.fromJson(jsonDecode(r'''
{
"stages": [
{
"type": "dom",
"input_mapping": {
"package_html": "/_body"
},
"output_fields": {
"package_html": {
"type": "field_selector",
"is_flatten": true,
"extractors": [
{
"type": "html_include",
"selector": "div[class=\"packages\"] div[class=\"packages-item\"]"
}
],
"collect_as": {
"type": "array",
"data_type": "html_element",
"default_value": null
}
}
},
"exclude_mapping": [
"/_body"
]
},
{
"type": "dom",
"input_mapping": {
"package_name": "/package_html",
"description": "/package_html",
"likes": "/package_html",
"health": "/package_html",
"popularity": "/package_html"
},
"output_fields": {
"package_name": {
"type": "field_selector",
"is_flatten": false,
"extractors": [
{
"type": "html",
"selector": "h3[class=\"packages-title\"]",
"collectors": [
"${text()}"
]
},
{
"type": "trim_string"
}
],
"collect_as": {
"type": "first",
"data_type": "string",
"default_value": null
}
},
"description": {
"type": "field_selector",
"is_flatten": false,
"extractors": [
{
"type": "html",
"selector": "p[class=\"packages-description\"]",
"collectors": [
"${text()}"
]
}
],
"collect_as": {
"type": "first",
"data_type": "string",
"default_value": null
}
},
"likes": {
"type": "field_selector",
"is_flatten": false,
"extractors": [
{
"type": "html",
"selector": "div[class*=\"packages-score-like\"] *[class=\"packages-score-value-number\"]",
"collectors": [
"${text()}"
]
}
],
"collect_as": {
"type": "first",
"data_type": "int",
"default_value": 0
}
},
"health": {
"type": "field_selector",
"is_flatten": false,
"extractors": [
{
"type": "html",
"selector": "div[class*=\"packages-score-health\"] *[class=\"packages-score-value-number\"]",
"collectors": [
"${text()}"
]
}
],
"collect_as": {
"type": "first",
"data_type": "int",
"default_value": 0
}
},
"popularity": {
"type": "field_selector",
"is_flatten": false,
"extractors": [
{
"type": "html",
"selector": "div[class*=\"packages-score-popularity\"] *[class=\"packages-score-value-number\"]",
"collectors": [
"${text()}"
]
}
],
"collect_as": {
"type": "first",
"data_type": "string",
"default_value": null
}
}
},
"exclude_mapping": [
"/package_html"
]
}
]
}
'''));
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Create a WebFlow

final flow = WebFlow(template);
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Download a web page and build a document

import 'dart:convert';

import 'package:http/http.dart' as http;

void main() async {

final response = await http.get('https://pub.dev/flutter/favorites');
final doc = response.body.asDocument('https://pub.dev');
}
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Start a flow and get the output result

import 'dart:convert';

import 'package:http/http.dart' as http;
import 'package:riverflow/riverflow.dart';

var records = flow.startFloating([doc.documentElement]);

records.forEach((record) {
print(jsonEncode(record.toJson()));
print('--------------------------\n');
});
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The result should look like this
[
{
"package_name": "shared_preferences",
"description": "Flutter plugin for reading and writing simple key-value pairs. Wraps NSUserDefaults on iOS and SharedPreferences on Android.",
"likes": 1233,
"health": 110,
"popularity": "100"
},
{
"package_name": "url_launcher",
"description": "Flutter plugin for launching a URL on Android and iOS. Supports web, phone, SMS, and email schemes.",
"likes": 858,
"health": 110,
"popularity": "100"
},
{
"package_name": "flutter_bloc",
"description": "Flutter Widgets that make it easy to implement the BLoC (Business Logic Component) design pattern. Built to be used with the bloc state management package.",
"likes": 821,
"health": 110,
"popularity": "99"
},
{
"package_name": "bloc",
"description": "A predictable state management library that helps implement the BLoC (Business Logic Component) design pattern.",
"likes": 440,
"health": 110,
"popularity": "99"
},
{
"package_name": "location",
"description": "A Flutter plugin to easily handle realtime location in iOS and Android. Provides settings for optimizing performance or battery.",
"likes": 333,
"health": 110,
"popularity": "99"
},
{
"package_name": "flutter_slidable",
"description": "A Flutter implementation of slidable list item with directional slide actions that can be dismissed.",
"likes": 623,
"health": 110,
"popularity": "98"
},
{
"package_name": "built_value",
"description": "Value types with builders, Dart classes as enums, and serialization. This library is the runtime dependency.\n",
"likes": 127,
"health": 110,
"popularity": "99"
},
{
"package_name": "convex_bottom_bar",
"description": "A Flutter package which implements a ConvexAppBar to show a convex tab in the bottom bar. Theming supported.",
"likes": 250,
"health": 110,
"popularity": "92"
},
{
"package_name": "provider",
"description": "A wrapper around InheritedWidget to make them easier to use and more reusable.",
"likes": 1736,
"health": 105,
"popularity": "100"
},
{
"package_name": "rxdart",
"description": "RxDart is an implementation of the popular reactiveX api for asynchronous programming, leveraging the native Dart Streams api.\n",
"likes": 535,
"health": 105,
"popularity": "100"
}
]
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