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Update: Docs updated, disable cache method
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Nodonisko committed Jul 21, 2016
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193 changes: 120 additions & 73 deletions README.md
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# Ionic 2 cache service
# Ionic cache service

My Ionic 2 cache service that can cache almost everything, include requests. It's made up to use WebSQL or SQLite
as storage and work well with Observables.
Ionic cache service that can cache almost everything. **It caches request, observables, promises and classic data.** It uses WebSQL or SQLite
as storage and work well with Observables. With few little changes it can be used separatelety in Angular 2 application.

**It's not well tested yet, so use it at your own risk.** Please report all bugs to bug report or fix it, or
better fix it and send pull request :)
Key features:
+ Request caching
+ Delayed observable caching (see docs for more info)
+ Don't invalidate cache if is browser offline
+ Set and invalidate groups of entries

Please report all bugs to bug report or fix it, or better fix it and send pull request :)

#### Contributors

Big thanks to all contributors for help. Currently only one Vojta Tranta, but I hope there will be more names in future :)

## Install

Simple copy file to your providers folder and inject it in *app.js* file.
Via NPM:

```js
import {CacheProvider} from "./providers/cache-provider/cache-provider";
```bash
npm install ionic-cache --save
cordova add plugin cordova-sqlite-storage --save
```

And inject service to your app:

```ts
import {CacheService} from "ionic-cache/ionic-cache";

@App({
templateUrl: "build/app.html",
providers: [CacheProvider]
templateUrl: "build/app.html"
})
class MyApp {
static get parameters() {
return [[IonicApp], [Platform], [CacheProvider]];
}

constructor(app, platform, cache) {
constructor(cache: CacheService) {
...
this.cache = cache;

this.cache.setTTL(60); //set default cache TTL for 1 minute
this.cache.setDefaultTTL(60 * 60); //set default cache TTL for 1 hour
....
}
...
}
ionicBootstrap(MyApp, [
CacheService
]);
```

## Usage

#### Cache request response body
#### Cache request

```js
import {CacheProvider} from '../cache-provider/cache-provider';
```ts
...
import {CacheService} from "ionic-cache/ionic-cache";

@Injectable()
export class CategoryProvider {
static get parameters() {
return [[Http], [CacheProvider]]
}

constructor(http, cache) {
export class SomeProvider {
constructor(http: Http, cache: CacheService) {
this.http = http;
this.cache = cache;
}

loadList() {
let url = "http://google.com";
let url = "http://ip.jsontest.com";
let cacheKey = url;

let request = this.http.get(url).map(res => res.json());
return this.cache.loadItem(cacheKey, request);

return this.cache.loadFromObservable(cacheKey, request);
}
...
```
#### Cache whole request response
Sometimes you need to cache whole response, if you need to look to Headers etc. It can be done only with simple
move *.map(res => res.json())* after *loadItem* method. *LoadItem* returns Observable, so you can also use other
Observable operators
move *.map(res => res.json())* after *loadFromObservable* method. *loadFromObservable* returns Observable, so you can also use other
Observable operators.
```js
...
let request = this.http.get(url);
return this.cache.loadItem(cacheKey, request).map(res => res.json());
return this.cache.loadFromObservable(cacheKey, request).map(res => res.json());
...
```
#### Cache classic data (arrays, objects, strings, numbers etc.)
Cache service works well with observables, but you can cache classic data as well.
```js
...
let key = 'heavily-calculated-function';

this.cache.getItem(key).catch(() => {
// fall here if item is expired or doesn't exist
let result = heavilyCalculatedFunction();
return this.cache.saveItem(key, result);
}).then((data) => {
console.log("Saved data: ", data);
});
...
```
#### Cache promises
```js
...
let key = 'some-promise';

this.cache.getItem(key).catch(() => {
// fall here if item is expired or doesn't exist
return somePromiseFunction().then(result => {
return this.cache.saveItem(key, result);
});
}).then((data) => {
console.log("Saved data: ", data);
});
...
```
#### Cache with custom Observable operators
*LoadItem* method using Observable and return Observable, so you can use lot of Observable operators.
For example error handling (on error, retry request every 6 seconds):
*loadFromObservable* method using Observable and return Observable, so you are free to use all Observable operators.
For example error handling (on error, retry request every 6 seconds if fails):
```js
...
let request = this.http.get(url)
.retryWhen((error) => {
return error.timer(6000);
}).map(res => res.json());
return this.cache.loadItem(cacheKey, request);
return this.cache.loadFromObservable(cacheKey, request);
...
```
#### Cache entries grouping
This is really nice feature. Sometimes you need to invalidate only some group of cache entries.
Sometimes you need to invalidate only some group of cache entries.
For example if you have have long infinite scroll with lots of pages, and user trigger pull to request you want to delete
all cache entries for all pages. So this is time for third parameter groupKey.
all cache entries for all pages. So this is time for third parameter.
```js
...
loadList(pageNumber) {
let url = "http://google.com/?page=" + pageNumber;
let cacheKey = url;
let groupKey = "googleListPages"
let groupKey = "googleSearchPages"

let request = this.http.get(url).map(res => res.json());
return this.cache.loadItem(cacheKey, request, groupKey);
return this.cache.loadFromObservable(cacheKey, request, groupKey);
}
...
```
And on pull to refresh delete all cache entries in group *googleListPages*:
And when pull to refresh is fired, delete all cache entries in group *googleListPages*:
```js
...
pullToRefresh() {
this.cache.removeByGroup("googleListPages");
this.cache.clearGroup("googleSearchPages");
}
...
```
#### Set custom TTL for single request
#### Delayed observable caching
If you want custom TTL for single request, it can by easily done by third parameter.
Features that using full power of observables. When you call this method and it will return data from cache (even if they are expired)
and immediately send request to server and return new data after request successfuly finish. See example for more details:
```js
...
loadList(pageNumber) {
...
let ttl = 60 * 60 * 24 * 7; // TTL in seconds for one week

let request = this.http.get(url).map(res => res.json());
return this.cache.loadItem(cacheKey, request, groupKey, ttl);
}
let delayType = 'all'; // send new request to server everytime, if it's set to none it will send new request only when entry is expired
let response = this.cache.loadFromDelayedObservable(cacheKey, request, groupKey, ttl, delayType);

response.subscribe(data => {
console.log("Data:" data);
});

//result will look like this:
// Data: "Hello world from cache"
// Data: "Hello world from server"
...
```
#### Cache non-observables (arrays, strings etc.)
#### Set custom TTL for single request
You can cache numbers, strings, arrays, objects etc.
If you want custom TTL for single request, it can by easily done by third parameter.
```js
...
let arrayToCache = ["Hello", "World"];
let key = 'test-array';
let ttl = 60 * 60 * 24 * 7; // TTL in seconds for one week
let request = this.http.get(url).map(res => res.json());

this.cache.saveItem(key, arrayToCache, null, 60).then((data) => {
console.log("Saved data: ", data);
});
return this.cache.loadFromObservable(cacheKey, request, groupKey, ttl);
```
this.cache.getItem(key).then((data) => {
console.log('Test of load saved data: ', data);
})
...
#### Set default TTL
```js
this.cache.setDefaultTTL(60 * 60); //set default cache TTL for 1 hour
```
#### Delete expired entries
It's automatically done on every startup, but you can do it manually.
```js
this.cache.removeExpired();
this.cache.clearExpired();
```
#### Delete all entries
```js
this.cache.removeAll();
```
#### Set default TTL
```js
this.cache.setDefaultTTL(60 * 60); //set default cache TTL for 1 hour
this.cache.clearAll();
```
#### Disable cache
If you are using *loadItem* method you can disable cache without any worrying, it will pass origin Observable through.
Other method will return Promise reject.
You can disable cache without any worrying, it will pass origin Observable through and all Promises will be rejected.
Without any errors.
```js
this.cache.enableCache = false; //Disable cache
this.cache.disableCache(true);
```
#### Disable offline invalidate
If you want disable "don't invalidate" when device is offline, you can do it simply.
For more inspiration look into code :)
```js
this.cache.setOfflineInvalidate(true);
```
2 changes: 1 addition & 1 deletion package.json
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@@ -1,6 +1,6 @@
{
"name": "ionic-cache",
"version": "1.0.4",
"version": "1.0.5",
"description": "Ionic cache service - cache request, data, promises etc.",
"main": "ionic-cache.js",
"scripts": {
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7 changes: 7 additions & 0 deletions src/cache.service.ts
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Expand Up @@ -34,6 +34,13 @@ export class CacheService {
}
}

/**
* @description Disable or enable cache
*/
public disableCache(status: boolean = true) {
this.enableCache = !status;
}

/**
* @description Create DB table for cache, if not exists
* @return {Promise<any>}
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