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Caching different http-requests

C# small caching APIMemcached cachingChaining HTTP requests becoming unreadableClass that make asynchronous http requestsCaching using phpFastCacheProxying Socket.io requests and other HTTP requestsAngular 2 / rxjs chaining HTTP callsChaining 3 dependent HTTP request subscriptions one, which is pollingChanging http-requests conditionallyRXJS queue up multiple http requests and send when x conditions happens

1

$begingroup$

There have been multiple discussions on caching http-requests with RXJS. In this question/proposal I want to propose a custom rxjs-operator (non-pure) to provide caching:

const cacheHttp = (cacheKey: string, cacheStorage: any) => (source: Observable<any>) => {

  if (!cacheStorage[cacheKey]) {

    cacheStorage[cacheKey] = source.pipe(

      shareReplay(1)

    );

  }

  return cacheStorage[cacheKey];

};

This operator is not pure, as it modifies one of its arguments (cacheStorage).

This operator could be used like this:

public cachedItems = {};



public getDataForItem$(itemId: string) {

    return this.http.get('/item/' + itemId).pipe(

        cacheHttp(itemId, this.cachedItems),

        shareReplay(1)

    );

}

The client could then call this multiple times without causing superfluous http-requests:

// the following two subscriptions cause http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// all further subscriptions would not cause any additional http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// this subscription would again cause an http-request:

this.itemService.getDataForItem('thirdItem').subscribe((val) => console.log(val));

Is this an acceptable approach to solving the "cache-for-different-requests-problem"? Is there possibly a memory-leak or are there any leaked subscriptions? Is it ok to have side-effects on a provided argument?

javascript cache angular-2+ rxjs

share|improve this question

edited 34 mins ago

Jamal♦

30.3k11119227

asked Feb 4 at 15:51

Tobias GassmannTobias Gassmann

1061

$endgroup$

add a comment | 

1

$begingroup$

There have been multiple discussions on caching http-requests with RXJS. In this question/proposal I want to propose a custom rxjs-operator (non-pure) to provide caching:

const cacheHttp = (cacheKey: string, cacheStorage: any) => (source: Observable<any>) => {

  if (!cacheStorage[cacheKey]) {

    cacheStorage[cacheKey] = source.pipe(

      shareReplay(1)

    );

  }

  return cacheStorage[cacheKey];

};

This operator is not pure, as it modifies one of its arguments (cacheStorage).

This operator could be used like this:

public cachedItems = {};



public getDataForItem$(itemId: string) {

    return this.http.get('/item/' + itemId).pipe(

        cacheHttp(itemId, this.cachedItems),

        shareReplay(1)

    );

}

The client could then call this multiple times without causing superfluous http-requests:

// the following two subscriptions cause http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// all further subscriptions would not cause any additional http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// this subscription would again cause an http-request:

this.itemService.getDataForItem('thirdItem').subscribe((val) => console.log(val));

Is this an acceptable approach to solving the "cache-for-different-requests-problem"? Is there possibly a memory-leak or are there any leaked subscriptions? Is it ok to have side-effects on a provided argument?

javascript cache angular-2+ rxjs

share|improve this question

edited 34 mins ago

Jamal♦

30.3k11119227

asked Feb 4 at 15:51

Tobias GassmannTobias Gassmann

1061

$endgroup$

add a comment | 

$begingroup$

There have been multiple discussions on caching http-requests with RXJS. In this question/proposal I want to propose a custom rxjs-operator (non-pure) to provide caching:

const cacheHttp = (cacheKey: string, cacheStorage: any) => (source: Observable<any>) => {

  if (!cacheStorage[cacheKey]) {

    cacheStorage[cacheKey] = source.pipe(

      shareReplay(1)

    );

  }

  return cacheStorage[cacheKey];

};

This operator is not pure, as it modifies one of its arguments (cacheStorage).

This operator could be used like this:

public cachedItems = {};



public getDataForItem$(itemId: string) {

    return this.http.get('/item/' + itemId).pipe(

        cacheHttp(itemId, this.cachedItems),

        shareReplay(1)

    );

}

The client could then call this multiple times without causing superfluous http-requests:

// the following two subscriptions cause http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// all further subscriptions would not cause any additional http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// this subscription would again cause an http-request:

this.itemService.getDataForItem('thirdItem').subscribe((val) => console.log(val));

Is this an acceptable approach to solving the "cache-for-different-requests-problem"? Is there possibly a memory-leak or are there any leaked subscriptions? Is it ok to have side-effects on a provided argument?

javascript cache angular-2+ rxjs

share|improve this question

edited 34 mins ago

Jamal♦

30.3k11119227

asked Feb 4 at 15:51

Tobias GassmannTobias Gassmann

1061

$endgroup$

const cacheHttp = (cacheKey: string, cacheStorage: any) => (source: Observable<any>) => {

  if (!cacheStorage[cacheKey]) {

    cacheStorage[cacheKey] = source.pipe(

      shareReplay(1)

    );

  }

  return cacheStorage[cacheKey];

};

public cachedItems = {};



public getDataForItem$(itemId: string) {

    return this.http.get('/item/' + itemId).pipe(

        cacheHttp(itemId, this.cachedItems),

        shareReplay(1)

    );

}

// the following two subscriptions cause http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// all further subscriptions would not cause any additional http-requests

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('firstItem').subscribe((val) => console.log(val));

this.itemService.getDataForItem('secondItem').subscribe((val) => console.log(val));



// this subscription would again cause an http-request:

this.itemService.getDataForItem('thirdItem').subscribe((val) => console.log(val));

share|improve this question

edited 34 mins ago

Jamal♦

30.3k11119227

asked Feb 4 at 15:51

Tobias GassmannTobias Gassmann

1061

share|improve this question

edited 34 mins ago

Jamal♦

30.3k11119227

asked Feb 4 at 15:51

Tobias GassmannTobias Gassmann

1061

edited 34 mins ago

Jamal♦

30.3k11119227

edited 34 mins ago

Jamal♦

30.3k11119227

asked Feb 4 at 15:51

Tobias GassmannTobias Gassmann

1061

asked Feb 4 at 15:51

Tobias GassmannTobias Gassmann

1061