[英]Returning API requests within loop nodejs
I have a loop with about 15 items and need to make two api calls each time the loop is iterated through. 我有一个约有15个项目的循环,每次循环迭代时都需要进行两个api调用。 So I need to make the API request within the loop and then do some simple calculation before the loop moves on. 因此,我需要在循环内发出API请求,然后在循环进行之前进行一些简单的计算。
Assume I have a function called getFlightData
that takes 3 parameters - a departing city, arriving city, and the date. 假设我有一个名为getFlightData
的函数,该函数带有3个参数-出发城市,到达城市和日期。 The function needs to make an API request and then return the JSON from the API call. 该函数需要发出API请求,然后从API调用返回JSON。
See my code below. 请参阅下面的代码。
const airportsList = [
"SFO",
"SEA",
"JFK",
"YTZ"
]
for (var i = 0; i < airportsList.length; i++) {
// loop through the airports
var departingFlightCost, returningFlightCost;
getFlightData("MEX", airportsList[i], date1);
getFlightData(airportsList[i],"MEX", date2);
}
function getFlightData(departingCity, arrivingCity, date) {
var options = {
method: 'GET',
url: 'https://apidojo-kayak-v1.p.rapidapi.com/flights/create-session',
qs: {
origin1: departingCity,
destination1: arrivingCity,
departdate1: date, //'2019-12-20',
cabin: 'e',
currency: 'USD',
adults: '1',
bags: '0'
},
headers: {
'x-rapidapi-host': 'apidojo-kayak-v1.p.rapidapi.com',
'x-rapidapi-key': API_KEY
}
};
request(options, function (error, response, body) {
const flightData = body;
});
}
Each time the loop iterates through a city, I need to get the contents of the two API requests and then do a simple calculation before moving on. 每次循环遍历一个城市时,我需要获取两个API请求的内容,然后在继续之前进行简单的计算。 How do I most effectively do this in node? 我如何最有效地在节点上执行此操作?
You can try this: 您可以尝试以下方法:
const getFlightData = (departingCity, arrivingCity, date) => new Promise((resolve, reject) => {
const options = {};
request(options, (error, res) => {
if (error) {
return reject(error);
}
return resolve(res);
});
});
const airportsList = [
"SFO",
"SEA",
"JFK",
"YTZ"
];
// things will run in parallel
for (let i = 0; i < airportsList.length; i++) {
const date1 = new Date();
const date2 = new Date();
const tasks = [
getFlightData("MEX", airportsList[i], date1),
getFlightData(airportsList[i], "MEX", date2)
];
// wait 2 tasks completed and handle
Promise.all(tasks)
.then(responses => {
const res1 = responses[0];
const res2 = responses[1];
// continue doing something here
})
.catch(error => {
// handle error here
})
}
Or if you want everything runs step by step, you can replace for loop
with this function: 或者,如果您希望一切逐步进行,则可以使用以下函数替换for loop
:
const syncLoop = i => {
const date1 = new Date();
const date2 = new Date();
const tasks = [
getFlightData("MEX", airportsList[i], date1),
getFlightData(airportsList[i], "MEX", date2)
];
// wait 2 tasks completed and handle
Promise.all(tasks)
.then(responses => {
const res1 = responses[0];
const res2 = responses[1];
// continue doing something here
// schedule a new function
syncLoop(i + 1);
})
.catch(error => {
// handle error here
})
};
syncLoop(0);
If you need to do something after all of async tasks were done: 如果您需要在完成所有异步任务之后执行一些操作:
const allTasks = [];
// things will run in parallel
for (let i = 0; i < airportsList.length; i++) {
const date1 = new Date();
const date2 = new Date();
const tasks = [
getFlightData("MEX", airportsList[i], date1),
getFlightData(airportsList[i], "MEX", date2)
];
// wait 2 tasks completed and handle
allTasks.push(Promise.all(tasks)
.then(responses => {
const res1 = responses[0];
const res2 = responses[1];
// continue doing something here
// remember to return something here
// things will appear in the below Promise.all
return res1;
})
.catch(error => {
// handle error here
})
);
}
Promise.all(allTasks)
.then(allResponses => {
// do something when all of async tasks above were done
})
.catch(error => {
// handle error here
});
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