Receiving a blank response after making a post request even though the request was processed without

Question

Receiving a blank response after making a post request even though the request was processed without

While making a post request using httpClient, I am receiving a null response despite the request being processed successfully.

File: serviceClass.ts

this.httpOptions = {
  headers: new HttpHeaders(
    { 
      'Content-Type': 'application/json; charset=utf-8',
      'tenant-code' : 'VdoFWiHL8RFR8fRGNjfZI=',
      'Authorization': 'Basic ' + btoa('pass:username')
    })
}

public Reprocess(ObjProduct) {
var Jobj=JSON.stringify(ObjProduct);
return this._http.post(this.ReprocessUrl,Jobj,this.httpOptions)
}

When invoking the above method in the Component, the response from the API is null.

Component Code

var op = this.objService.reprocess(this.reprobj);
console.log("output: ", op);

The value of op seems to be incorrect, displaying _scaler=false among other things. How can I obtain the accurate status of the service call?

Edit 1: Making the same request from Postman yields a status of Ok 200.

Edit 2: The code below is also resulting in a null response (as per the @Spart_Fountain's answer)

var op= this.restApi.Reprocess(this.reprobj).subscribe((data:any) => {
console.log("data "+ data);    
});

Postman header screenshot

https://i.sstatic.net/LzV2r.png

angular typescript httprequest

Answer 1

Answer №1

When you call

this.objService.reprocess(this.reprobj);

, the response may appear unusual because the method returns a Subscription object.

Essentially, the reprocess method returns a subscription to an observable because it internally calls the subscribe() method within the same return statement. To avoid this, it is advisable to return only the observable and subscribe to it outside of the reprocess method:

public reprocess(objProduct) {
  var objParam = JSON.stringify(objProduct);
  return this._http.post(this.url, objParam, this.httpOptions);
}

var op = this.objService.reprocess(this.reprobj).subscribe(resp => {
  console.log("resp from api service: " + resp);
});

Answer 2

When you call

this.objService.reprocess(this.reprobj);

, the response may appear unusual because the method returns a Subscription object.

Essentially, the reprocess method returns a subscription to an observable because it internally calls the subscribe() method within the same return statement. To avoid this, it is advisable to return only the observable and subscribe to it outside of the reprocess method:

public reprocess(objProduct) {
  var objParam = JSON.stringify(objProduct);
  return this._http.post(this.url, objParam, this.httpOptions);
}

var op = this.objService.reprocess(this.reprobj).subscribe(resp => {
  console.log("resp from api service: " + resp);
});

Answer 3

Answer №2

Your provided code snippet appears to be functioning correctly, and you have verified that your backend API is updating the database properly when tested with Postman.

Confirm if your database is being updated when using the method mentioned in your post. If not, the issue likely lies in the frontend code. Double-check that the correct parameters are being passed in the post method.
If the database is updating but you are not receiving a response, it is possible that the API is not sending any response. In this case, review your API code for any errors.

Answer 4

Your provided code snippet appears to be functioning correctly, and you have verified that your backend API is updating the database properly when tested with Postman.

Confirm if your database is being updated when using the method mentioned in your post. If not, the issue likely lies in the frontend code. Double-check that the correct parameters are being passed in the post method.
If the database is updating but you are not receiving a response, it is possible that the API is not sending any response. In this case, review your API code for any errors.

Answer 5

Answer №3

The null value seen in the log is actually the expected behavior of the http client. By default, it only looks at the response body, so receiving a null value means you have already received a 200 OK status with an empty body. To see the entire response, you can use the following code:

this.httpOptions = {
   headers: new HttpHeaders(
     { 
       'Content-Type': 'application/json; charset=utf-8',
       'tenant-code' : 'VdoFWiHL8RFR8fRGNjfZI=',
       'Authorization': 'Basic ' + btoa('pass:username')
     }),
     {
       observe: 'response'
     }
}

Answer 6

The null value seen in the log is actually the expected behavior of the http client. By default, it only looks at the response body, so receiving a null value means you have already received a 200 OK status with an empty body. To see the entire response, you can use the following code:

this.httpOptions = {
   headers: new HttpHeaders(
     { 
       'Content-Type': 'application/json; charset=utf-8',
       'tenant-code' : 'VdoFWiHL8RFR8fRGNjfZI=',
       'Authorization': 'Basic ' + btoa('pass:username')
     }),
     {
       observe: 'response'
     }
}

Answer 7

Answer №4

Here is a suggestion to try:

this.objectService.reprocess(this.reprObj).subscribe(resp => {
   console.log(resp);
})

The code above subscribes to the reprocess method. Inside the reprocess method, you will find the following import statement:

import {HttpClient} from '@angular/common/http';
constructor(private http: HttpClient) { }

reprocess(objProduct) {
   const formData: FormData = new FormData();
   formData.append('object', objProduct)
   return(
     this.http.post(this.url, formData)
   )
}

Make sure to handle the objProduct on your server side.

Answer 8

Here is a suggestion to try:

this.objectService.reprocess(this.reprObj).subscribe(resp => {
   console.log(resp);
})

The code above subscribes to the reprocess method. Inside the reprocess method, you will find the following import statement:

import {HttpClient} from '@angular/common/http';
constructor(private http: HttpClient) { }

reprocess(objProduct) {
   const formData: FormData = new FormData();
   formData.append('object', objProduct)
   return(
     this.http.post(this.url, formData)
   )
}

Make sure to handle the objProduct on your server side.

Answer 9

Answer №5

It is necessary to subscribe to the Reprocess function in order to proceed.

Don't forget to include an error callback function in your subscription to handle any errors that may arise during the post attempt.

Take advantage of the developer tools in your browser by checking the Network tab to observe the requests, responses, and headers exchanged when sending a request from your Angular application.

Ensure the following response headers are present in the Network tab:

Access-Control-Allow-Credentials: true
Access-Control-Allow-Origin: (Your url e.g. localhost:4200)

Confirm that your origin is allowed to make the request.

Check for any error messages related to 'WWW-Authenticate:', such as an invalid token.

Call the subscribe function from your component to the Reprocess service function like so:

this.objService.reprocess(this.reprobj).subscribe(result =>
{
console.log(result);
},
error => {
 console.log(error);
}
);

You may modify the service function to explicitly display the returned data (Observable to subscribe to):

public reprocess(objProduct): Observable<any> {
  var objParam = JSON.stringify(objProduct);
  return this._http.post<any>(this.url, objParam, this.httpOptions);
}

Ensure that the Observable is imported into your service:

import { Observable } from 'rxjs/Observable';

If everything is working fine in Postman and you are confident in the credentials, focus on the mentioned code changes, particularly importing the Observable and calling the function with subscribe. Any error related to missing the Observable import will be highlighted in your code.

Answer 10

It is necessary to subscribe to the Reprocess function in order to proceed.

Don't forget to include an error callback function in your subscription to handle any errors that may arise during the post attempt.

Take advantage of the developer tools in your browser by checking the Network tab to observe the requests, responses, and headers exchanged when sending a request from your Angular application.

Ensure the following response headers are present in the Network tab:

Access-Control-Allow-Credentials: true
Access-Control-Allow-Origin: (Your url e.g. localhost:4200)

Confirm that your origin is allowed to make the request.

Check for any error messages related to 'WWW-Authenticate:', such as an invalid token.

Call the subscribe function from your component to the Reprocess service function like so:

this.objService.reprocess(this.reprobj).subscribe(result =>
{
console.log(result);
},
error => {
 console.log(error);
}
);

You may modify the service function to explicitly display the returned data (Observable to subscribe to):

public reprocess(objProduct): Observable<any> {
  var objParam = JSON.stringify(objProduct);
  return this._http.post<any>(this.url, objParam, this.httpOptions);
}

Ensure that the Observable is imported into your service:

import { Observable } from 'rxjs/Observable';

If everything is working fine in Postman and you are confident in the credentials, focus on the mentioned code changes, particularly importing the Observable and calling the function with subscribe. Any error related to missing the Observable import will be highlighted in your code.

Answer 11

Answer №6

 function processProduct(product) {
 var parameters = JSON.stringify(product);
 return this._http.post(this.url, parameters, this.httpOptions);
 }`var response = this.productService.process(this.productObj).subscribe(reply =>{
 console.log("Response from API service: " + reply);
 });

Answer 12

 function processProduct(product) {
 var parameters = JSON.stringify(product);
 return this._http.post(this.url, parameters, this.httpOptions);
 }`var response = this.productService.process(this.productObj).subscribe(reply =>{
 console.log("Response from API service: " + reply);
 });

Receiving a blank response after making a post request even though the request was processed without

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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