130 lines
3.0 KiB
Markdown
130 lines
3.0 KiB
Markdown
# DataExtracter Help
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----------------------------
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DataExtracter helps you quickly extract data from any web pages.
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All you need to do is:
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- Find out the selectors for target data
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- Type scripts in the console of `extension backgroud page`, as introduced bellow.
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## Qucik Start
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Extract current page
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```js
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$('.item', ['a', 'a@href']);
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```
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Extract multiple pages (1-10, interval 1)
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```js
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$('.item', ['a', 'a@href'],"http://sample.com/?pn=${page}", 1, 10, 1);
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```
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Extract multiple urls (list)
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```js
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$('.item', ['a', 'a@href'],["http://sample.com/abc","http://sample.com/xyz"]);
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```
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Extract specified pages (1,3,5)
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```js
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$('.item', ['a', 'a@href'], "http://sample.com/?pn=${page}", [1, 3, 5]);
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```
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## Task Call Signitures
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```ts
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// extract data from current page
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function (itemsSelector:string, fieldSelectors:string[])
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// extract data from a range of pages
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function (itemsSelector:string, fieldSelectors:string[], urlTemplate:string, from:number, to:number, interval:number)
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// extract data from a list of pages
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function (itemsSelector:string, fieldSelectors:string, urlTemplate:string, pages:number[])
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// extract data from a list of pages
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function (itemsSelector:string, fieldSelectors:string[], urls:string[])
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// extract data of urls which extracted from last task result
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function (itemsSelector:string, fieldSelectors:string[], urls:ExtractResult)
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```
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## Stop Tasks
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The only way to stop tasks before its finish, is `Closing the target tab`.
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> Tasks wait for their target elements' appearance, given some elements were loaded asynchronously.
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> If you typed wrong selectors, the task waits forever for elements which don't exists.
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## Extract Attributes.
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e.g.: link text and target (use 'selector@attribute')
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```js
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new Extractor().task('.item', ['a', 'a@href']).start();
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```
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## Advanced Usage
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### Use Task Chain.
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e.g.: Collect links from `http://sample.com/abc`, then, Extract data of each link
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```js
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e = new Extractor()
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e.task('.search-list-item', ['a@href'], ["http://sample.com/abc"])
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.task('list-item', ["a.title", "p.content"])
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.start();
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```
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### Continue Tasks
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You can always continue tasks (with following), even it stops in the middle of a task:
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```js
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e.start()
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```
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The `Extractor` kept the state of last execution, and starts from where it stopped.
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### Restart Tasks
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What should I do, if I don't like to continue from last state, but restart from certain task?
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```js
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// restart all tasks
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e.restart(0)
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// restart from 2nd task
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e.restart(1)
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```
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### Save Result of Any Task
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To a multiple task Extractor `e`:
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```js
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e = new Extractor()
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e.task('.search-list-item', ['a@href'], ["http://sample.com/abc"])
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.task('list-item', ["a.title", "p.content"])
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.start();
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```
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User will be asked to save the final result when it finishes.
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Incase you want to save it again, use:
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```js
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e.save()
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```
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To save another task result, other than the final one:
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```js
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// save the result of first task
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// to the example above, that is a list of urls
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e.save(0)
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// save the result of second task
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e.save(1)
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```
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