134 lines
3.3 KiB
Markdown
134 lines
3.3 KiB
Markdown
# DataExtracter Help
|
|
----------------------------
|
|
|
|
DataExtracter helps you quickly extract data from any web pages.
|
|
|
|
All you need to do is:
|
|
|
|
- Find out the selectors (JQuery selectors) for target data
|
|
- Type scripts in the console of `extension backgroud page`, as introduced bellow.
|
|
|
|
|
|
|
|
## Qucik Start
|
|
|
|
Extract current page
|
|
```js
|
|
new Extractor().task(".list-item", ["a.title", "p.content"]).start();
|
|
```
|
|
|
|
Extract multiple pages (1-10, interval 1)
|
|
|
|
```js
|
|
new Extractor().task(".list-item", ["a.title", "p.content"],"http://sample.com/?pn=${page}", 1, 10, 1).start();
|
|
```
|
|
|
|
Extract multiple urls (list)
|
|
|
|
```js
|
|
new Extractor().task(".list-item", ["a.title", "p.content"],["http://sample.com/abc","http://sample.com/xyz"]).start();
|
|
```
|
|
|
|
Extract specified pages (1,3,5)
|
|
|
|
```js
|
|
new Extractor().task(".list-item", ["a.title", "p.content"], "http://sample.com/?pn=${page}", [1, 3, 5]).start();
|
|
```
|
|
|
|
## Extractor.task() Signitures
|
|
|
|
```ts
|
|
// a task extracting data from current page
|
|
task(itemsSelector:string, fieldSelectors:string[])
|
|
// a task extracting data from a range of pages
|
|
task(itemsSelector:string, fieldSelectors:string[], urlTemplate:string, from:number, to:number, interval:number)
|
|
// a task extracting data from a list of pages
|
|
task(itemsSelector:string, fieldSelectors:string, urlTemplate:string, pages:number[])
|
|
// a task extracting data from a list of pages
|
|
task(itemsSelector:string, fieldSelectors:string[], urls:string[])
|
|
// a task extracting data of urls which extracted from last task result
|
|
task(itemsSelector:string, fieldSelectors:string[], urls:ExtractResult)
|
|
```
|
|
|
|
## Advanced Usage
|
|
|
|
### Stop Tasks
|
|
|
|
Tasks wait for their target elements' appearance, given some elements were loaded asynchronously.
|
|
|
|
But if you typed wrong selectors, the task waits forever for elements which don't exists.
|
|
|
|
The only way to stop tasks before its finish, is `Closing the host tab`.
|
|
|
|
### Extract Attributes.
|
|
|
|
e.g.: link text and target (use 'selector@attribute')
|
|
|
|
```js
|
|
new Extractor().task('.list-item', ['a.title', 'a.title@href']).start();
|
|
```
|
|
|
|
### Use Task Chain.
|
|
|
|
e.g.: Collect links from `http://sample.com/abc`, then, Extract data of each link
|
|
|
|
```js
|
|
new Extractor()
|
|
.task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
|
|
.task('list-item', ["a.title", "p.content"])
|
|
.start();
|
|
```
|
|
|
|
### Save Result of Any Task
|
|
|
|
To a multiple task (chain) Extractor `e`:
|
|
|
|
```js
|
|
e = new Extractor()
|
|
e.task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
|
|
.task('list-item', ["a.title", "p.content"])
|
|
.start();
|
|
```
|
|
|
|
User will be asked to save the final result when it finishes.
|
|
|
|
Incase you want to save it again, use:
|
|
|
|
```js
|
|
e.save()
|
|
```
|
|
|
|
You may want to save another task's result, other than the final:
|
|
|
|
```js
|
|
// save the result of first task
|
|
// to the example above, that is a list of urls
|
|
e.save(1)
|
|
```
|
|
|
|
### Restart Tasks
|
|
|
|
In cases some later task fails, you don't need to restart all task.
|
|
|
|
Here we have 2 tasks:
|
|
|
|
```js
|
|
e = new Extractor()
|
|
e.task('.search-list-item', ['.item a@href'], ["http://sample.com/abc"])
|
|
.task('list-item', ["a.title", "p.content"])
|
|
.start();
|
|
```
|
|
|
|
Suppose the second task fails, we can restart and continue from the task 2:
|
|
|
|
```js
|
|
e.restart(2);
|
|
```
|
|
|
|
If you'd like restart all task, use:
|
|
|
|
```js
|
|
e.start();
|
|
// or
|
|
e.restart();
|
|
``` |