I try to get the JSON data from a GET request and I can see the information from body in request. How can I get the data?
Currently use NodeJs, basic in JavaScript.
var definedURL="https://api.etherscan.io/api?module=account&action=tokentx&contractaddress=0x6a750d255416483bec1a31ca7050c6dac4263b57&page=1&offset=100&sort=asc&apikey=YourApiKeyToken";
var request = require('request')
var information=[];
request({
url: definedURL,
json: true
}, function (error, response, body) {
if (!error && response.statusCode === 200) {
//console.log(body.result[0]);
information.push(body.result[0]);
}
});
console.log(information);
I expect after this I will see the contain of result coming out, but now it still shows [].
Because you are making asynchronous request. Asynchronous action will get completed after the main thread execution.
console.log(information) // execute before your call
You need to wait for the request call to get completed and received data get pushed to information
There can be two ways to do this -
Async/Await- MDN Reference
var definedURL="https://api.etherscan.io/api?module=account&action=tokentx&contractaddress=0x6a750d255416483bec1a31ca7050c6dac4263b57&page=1&offset=100&sort=asc&apikey=YourApiKeyToken";
var request = require('request')
var information=[];
async () => {
await request({
url: definedURL,
json: true
}, function (error, response, body) {
if (!error && response.statusCode === 200) {
//console.log(body.result[0]);
information.push(body.result[0]);
}
});
console.log(information)
}();
Promise MDN reference
var definedURL="https://api.etherscan.io/api?module=account&action=tokentx&contractaddress=0x6a750d255416483bec1a31ca7050c6dac4263b57&page=1&offset=100&sort=asc&apikey=YourApiKeyToken";
var request = require('request')
var information=[];
var Promise = new Promise((resolve,reject) => {
request({
url: definedURL,
json: true
}, function (error, response, body) {
if (!error && response.statusCode === 200) {
//console.log(body.result[0]);
information.push(body.result[0]);
resolve()
}
});
})
Promise.then(() => {
console.log(information)
})
Related
Alright. Trying to make a very simple request here. First code with asynchronous Nodejs. According to everywhere I've checked, I'm doing this right. None of them explained really how callbacks work, they just say what to do, so I have no way of figuring it out intuitively.
const request = require("request");
function fetchData(url, json, callback) {
request({
url: url,
json: json,
method: "get"
}, callback(error, response, body))
}
console.log(fetchData("https://www.yahoo.com", false, function(error, response, body) {
if(!error && response.statusCode == 200) {
return body;
} else {
return error;
}
}));
Thanks
Two things- first, pass the callback variable into request(), don't call the function.
callback vs callback()
Second, you can't use the return value from the callback function. Call console.log() from inside the callback function.
Code with changes:
const request = require("request");
function fetchData(url, json, callback) {
request({
url: url,
json: json,
method: "get"
}, callback)
}
fetchData("http://www.yahoo.com", false, function(error, response, body) {
if(!error && response.statusCode == 200) {
console.log(body);
} else {
console.log(error);
}
}));
I am new in nodejs and I am using express js, I am calling REST API and want to show the response, but my problem is that the response is showing in console.log but I want to pass the body(response) in assistant.ask, where I am wrong here is my code:
var request = require('request');
let rawInput = function (assistant) {
let rawInput = assistant.getRawInput();
request.post(
'http://xxxxxxx.ngrok.io/api/v1/240/respond',
{ json: { query: rawInput } },
function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log(body);
assistant.ask(body);
}
else{
console.log(error);
}
}
);
How to make a proper post request to this endpoint. When I use the POSTMAN I get the correct response but when I call using the below function I get 503 error. The call seems to be fine according to me. I appreciate your help!!
const request = require('request');
const express = require('express');
// Initialize request
var img64Data = "/9j/4AAQSkZJRgABAQAAAQABAAD/2w… "; // Include the entire base64 encoding. // Shown Below in the next page
var send = {"img64": img64Data};
var api_address = "https://8n78hbwks0.execute-api.us-west-2.amazonaws.com/dev/";
// Make Post Request
module.exports = app => {
app.post('/axe', (req, res, next) => {
console.log("inside the axe");
request.post({
url: api_address,
body: JSON.stringify(send),
headers: {"Content-Type":"application/json"}
}, function (error, response, body) {
console.log("hiii");
console.log(response.statusCode);
if (!error && response.statusCode == 200) {
// Successful call
var results = JSON.parse(body);
console.log(results) // View Results
}
});
});
};
You get a 503 Error https://en.wikipedia.org/wiki/List_of_HTTP_status_codes because your server doesn't reply any http code.
if (!error && response.statusCode == 200) {
// Successful call
var results = JSON.parse(body);
console.log(results) // View Results
res.sendStatus(200);
} else {
res.sendStatus(response.statusCode);
}
Still learning node. Based upon the following:
https://github.com/request/request
var request = require('request');
request('http://www.google.com', function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log(body) // Show the HTML for the Google homepage.
}
})
I wish to create the above as a reusable block of code so thought I'd wrap it in a function passing the URL as a parameter such as:
var request = require('request');
var URL;
var request = require('request');
request('http://www.google.com', function (error, response, body) {
if (!error && response.statusCode == 200) {
console.log(body) // Show the HTML for the Google homepage.
}
})
function fetchURL (URL) {
request(URL, function (error, response, body) {
if (!error && response.statusCode == 200) {
return body;
}
});
};
var a = fetchURL('http://www.google.com');
console.log(a);
This works however I am unsure of whether "return body" is needed as it also works without this line. Happy to received comments on my coding style too as it's all new to me.
The pattern in Node is to provide a callback as an argument to an asynchronous function. By convention, this callback function has error as its first argument. For example:
function fetchURL(url, callback) {
request(url, function(error, response, body) {
if (!error && response.statusCode == 200) {
callback(null, body);
} else {
callback(error);
}
});
};
fetchURL('http://www.google.com', function(err, body) {
console.log(body);
});
Note that in your snippet, return body; is a return from the anonymous callback function passed into fetchURL(). fetchURL() itself returns nothing.
In one of the examples in the request's documents shows this example:
https://www.npmjs.com/package/request#custom-http-headers
var request = require('request');
var options = {
url: 'https://api.github.com/repos/request/request',
headers: {
'User-Agent': 'request'
}
};
function callback(error, response, body) {
if (!error && response.statusCode == 200) {
var info = JSON.parse(body);
console.log(info.stargazers_count + " Stars");
console.log(info.forks_count + " Forks");
}
}
request(options, callback)
Lets' say I want the value of the variable info return to me.
How do I do it?
You cannot pass a value from an asynchronous command. The most common strategy used in Node.js is to wrap the code that requires the info variable in a function and call that from the callback.
eg:
function callback(error, response, body) {
if (!error && response.statusCode == 200) {
functionThatUsesInfo(info);
}
}