I was able to use the code in this answer to access a value in a JSON string posted to the server.
If the server gets {"MyKey":"My Value"} then the value for "MyKey" can be accessed with request.body.MyKey.
But the JSON strings that get sent to my server look like this:
[{"id":"1","name":"Aaa"},{"id":"2","name":"Bbb"}]
I could not find a way to access anything in that. How do you do it?
request.body is a standard JavaScript object and in your case a vanilla JavaScript array. You would just handle request.body like you would any JavaScript Array object. e.g.
app.post('/', function(request, response){
var users = request.body;
console.log(users.length); // the length of the array
var firstUser = users[0]; // access first element in array
console.log(firstUser.name); // log the name
users.forEach(function(item) { console.log(item) }); // iterate the array logging each item
...
Related
I am trying to fetch a simple JSON element from express.js. I am trying have React assign it to a state variable on the front end. I am using this code to do so:
componentDidMount() {
fetch("/user")
.then(response => response.json())
.then(result => this.setState({myUser:result}))
}
But when I run typeof myUser after this setState command, it says string instead of object. I've tried using JSON.parse(), etc. But either I get an error or it continues to assign the data as a string rather than JSON. What sort of syntax do I need to use in this fetch-then context to coerce the data assignment to be JSON?
I have read this link:
With this code:
componentDidMount(){
fetch('https://abx.com/data/tool.json').then(response =>{
if (!response.ok) throw Error('Response not ok')
return response.json(); // This is built in JSON.parse wrapped as a Promise
}).then(json => {
this.setState({"sections" : json});
}).catch(err =>{
console.log(err);
});
}
But it doesn't solve the problem. I ran this code directly in my application verbatim. When I run typeof on the variable, it says string instead of object. I looked at other posts on Stack Overflow, but I did not see a solution to this.
I figured out what was going wrong (after many hours of experimenting):
On the server side, I was creating a "homegrown" JSON object using string and variable concatenation. I also tried creating the JSON object by doing this:
var str = "name:" + name + ", department:" + department
var user = {str};
Both of these were not working in subtle ways... despite trying different types of gadgetry on the client side, I couldn't get React to interpret the data as a JSON object. But then I had an idea to construct the JSON on the server side (in Express.js) like this:
var user = {};
user["name"] = name;
user["department"] = department;
That immediately cleared things up on the server side and the client side. When using setState() in React, it now sets the value as an object (which was the goal all along).
I think this can be useful to others... if React doesn't seem to understand the JSON, perhaps it is being sent from the server in a subtly incorrect format.
I'm using axios to send a JSON object as a parameter to my api. Before it post request is fired, my data starts of as a JSON object. On the server side, when I console.log(req.params) the data is returned as such
[object Object]
When I used typeof, it returned a string. So then I went to use JSON.parse(). However, when I used that, it returned an error as such
SyntaxError: Unexpected token o in JSON at position 1
I looked for solutions, but nothing I tried seemed to work. Now I'm thinking I'm sending the data to the server incorrectly.
Here's my post request using axios:
createMedia: async function(mediaData) {
console.log("SAVING MEDIA OBJECT");
console.log(typeof mediaData)
let json = await axios.post(`http://localhost:3001/api/media/new/${mediaData}`)
return json;
}
Any thoughts on how I can solve this?
You need to update your code using axios to provide the mediaData in the body of the request instead of the URL:
createMedia: async function(mediaData) {
console.log("SAVING MEDIA OBJECT");
console.log(typeof mediaData)
let json = await axios.post(`http://localhost:3001/api/media/new/`, mediaData)
return json;
}
In the backend (assuming you're using express here), you need to configure your application to use bodyParser:
var express = require('express')
, app = express.createServer();
app.use(express.bodyParser());
And then in your controller update your console.log(req.params) to console.log(req.body); then restart your node server
I am a newcomer to Meteor and am struggling to convert an external service response format as JSON to a 'parseable' format
Code on server side:
if(result){
console.log("fred" + result);
console.log(EJSON.stringify(result, {indent: true}));
var myObj = result;
console.log(myObj.count);
}
The first log statment (server-side) shows that it is an object
The second shows that data has been validly return (via callback)
The third shows undefined as unsuccessful attempt to parse as array.
Then the documentation loses me on how I can query the response for specific elements. Am I forced to parse client side?
I'm using node, express, and mongoose.
I have a function that performs a search in a database and sends the response in a JSON format with:
res.jsonp(search_result);
This displays the correctly returned result in the browser as a JSON object. My question is, how do I get that JSON object?
I've tried returning search_result but that gives me null (possibly because asynchronous). I'd also like to not edit the current function (it was written by someone else). I'm calling the function and getting a screen full of JSON, which is what res.jsonp is supposed to do.
Thanks in advance.
Just make a new function that takes this JSON as parameter and place it inside the old one. Example:
// Old function
app.get('/', function(req,res){
// recieve json
json_object = .....
// Get json to your function
processJson(json_object);
// Old function stuff
.
.
.
});
function processJson(json_object) {
// Here you'll have the existing object and can process it
json_object...
}
I have a rest service for which I am sending the Json data as ["1","2","3"](list of strings) which is working fine in firefox rest client plugin, but while sending the data in application the structure is {"0":"1","1":"2","2":"3"} format, and I am not able to pass the data, how to convert the {"0":"1","1":"2","2":"3"} to ["1","2","3"] so that I can send the data through application, any help would be greatly appreciated.
If the format of the json is { "index" : "value" }, is what I'm seeing in {"0":"1","1":"2","2":"3"}, then we can take advantage of that information and you can do this:
var myObj = {"0":"1","1":"2","2":"3"};
var convertToList = function(object) {
var i = 0;
var list = [];
while(object.hasOwnProperty(i)) { // check if value exists for index i
list.push(object[i]); // add value into list
i++; // increment index
}
return list;
};
var result = convertToList(myObj); // result: ["1", "2", "3"]
See fiddle: http://jsfiddle.net/amyamy86/NzudC/
Use a fake index to "iterate" through the list. Keep in mind that this won't work if there is a break in the indices, can't be this: {"0":"1","2":"3"}
You need to parse out the json back into a javascript object. There are parsing tools in the later iterations of dojo as one of the other contributors already pointed out, however most browsers support JSON.parse(), which is defined in ECMA-262 5th Edition (the specification that JS is based on). Its usage is:
var str = your_incoming_json_string,
// here is the line ...
obj = JSON.parse(string);
// DEBUG: pump it out to console to see what it looks like
a.forEach(function(entry) {
console.log(entry);
});
For the browsers that don't support JSON.parse() you can implement it using json2.js, but since you are actually using dojo, then dojo.fromJson() is your way to go. Dojo takes care of browser independence for you.
var str = your_incoming_json_string,
// here is the line ...
obj = dojo.fromJson(str);
// DEBUG: pump it out to console to see what it looks like
a.forEach(function(entry) {
console.log(entry);
});
If you're using an AMD version of Dojo then you will need to go back to the Dojo documentation and look at dojo/_base/json examples on the dojo.fromJson page.