CODEWITHSUNDEEP
javascriptnode.jsjsonhttprequest
nicodp
nicodp

Reputation: 2392

Execute HTTP requests in by-pass order

What I would like to achieve is to execute synchronously an ordered sequence of HTTP requests, but depending on the value of some variables, I want some of them to be by-passed.

As an example (I am using the request library in Javascript to do so):

request(httpReq1, function(error, response, body) {
  // do something, like handling errors...
  request(httpReq2, function(error, response, body) {
    // do something else
  });
});

So this ensures that httpReq2 will execute after httpReq1.

What I am not sure is how to by-pass the first request if, for example, some flag is set to false, and instead of executing httpReq1 and wait for a response, it just jumps to httpReq2, keeping the order:

if (dontMakeHttpReq1) // where should this be placed?

request(httpReq1, function(error, response, body) {
  // do something, like handling errors...
  request(httpReq2, function(error, response, body) {
    // do something else
  });
});

What would be a good approach to solve this?

Upvotes: 0

Views: 94

Answers (3)

user10251509
user10251509

Reputation:

Why not using 2 conditions?

if (dontMakeHttpReq1) {
  request(req1, function(error, response, body) {
    yourRequestProcessing2();
  });
}
else {
  request(req1, function(error, response, body) {
    request(req2, function(error, response, body) {
      yourRequestProcessing2();
    });
    yourRequestProcessing1();
  });
}

Edit: Maybe you want to store the request calls in arrays

//Whether request n should skip
var flags = [
  false,
  true,
  false
];
var requests = [
  function(error, response, body) {
    //Process your request 1
  },
  function(error, response, body) {
    //Process your request 2
  },
  function(error, response, body) {
    //Process request 3
  }
];
for (i = 0; i < requests.length; i++) {
  if (flags[i]) {
    request(req1, requests[i + 1]);
  }
  else {
    request(req2, request[i]);
  }
}

Upvotes: 1

Rick Su
Rick Su

Reputation: 16440

Sort out a list of requests needed in an array, and execute them sequentially using the async/await

let requests = [];
if (doRequest1)
  requests.push(httpReq1);

if (doRequest2)
  requests.push(httpReq2);

/* etc .. for httpReq3 and so on */

// now execute them one by one in sequence
for(let req of requests) {
   try {
     await request(req);
   } catch (err) {
     // error handling here
   }
}

Upvotes: 2

hdk
hdk

Reputation: 870

You can use async-await to achieve that.

async apiCall(){ 
    try{
     if(condition){
      const result1 = await request(httpReq1);
     }
     const result2 = await request(httpReq2);
    }
    catch(error){

    }
}

make sure that request module retruns a promise. Otherwise create a promise wrapper. axios is a library that is promise based.

You have to put async before the function that includes your awaits

Upvotes: 1

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