I am wondering how to parse a result after a query in azure using Easy API in Azure? For me, it seems that creating an objet inside the function(results) would lead to an endless loop and in the end, return httpcode 500.
Please help. There must be a way to parse the result, store it in a Javascript object and then return that result as a Json.
var azureMobileApps = require('azure-mobile-apps');
var queries = require('azure-mobile-apps/src/query');
var api = {
get: (req, res, next) => {
if(Object.keys(req.query).length === 0) {
res.status(400).type('text/plain').send("Error! Please add event id");
return;
}
if(req.query.eventId === 'undefined' || req.query.eventId.length === 0) {
res.status(400).type('text/plain').send("Error! missing eventId parameter");
console.log("worked!");
return;
}
var query = {
sql: 'Select .... where eventId=#eventId'
,
parameters: [
{ name: 'eventId', value: req.query.eventId }
]
};
req.azureMobile.data.execute(query)
.then(function (results) {
TODO: here! Parse results, add properties to objects and then return that instead!
res.status(200).type('application/json').send({sessions: results});
},function(error){
console.log('Found an error: ', error);
});
}
};
api.get.access = 'authenticated';
module.exports = api;
Your code snippet don't have any problem. In node.js backend Mobile Apps, the req.azureMobile.data.execute(query) returns an array list of queried results. Here is a code sample on GitHub https://github.com/Azure/azure-mobile-apps-node/blob/master/samples/custom-api-sql-stmt/api/completeall.js provided by Azure Dev Team.
And Mobile App in Node.js is based on Expressjs framework. You can simply use res.json(obj) to directly return a json response.
Separately for your issue, usually, the stmt exception will raise your issue. Please double check your query object whether it is correct before it querying data.
You can use Visual Studio Team Services (was Visual Studio Online) for troubleshooting of nodejs backend Mobile Apps.
Any further concenr, please feel free to let me know.
Related
The Nodejs functions return an error from try/catch scope, such as the one below if the user doesn't exist of if a database is not reachable:
router.delete('/delete/:email', async (req, res) => {
var email = req.params.email;
try {
let result = await User.remove({"email": email});
res.status(204).send(email);
} catch (err) {
res.status(400).send(err);
}
});
I can also return the Error from Nodejs server by myself:
return res.status(400).send(new Error(`The user with email ${email} doesn't exist.`));
The first problem is that I can't find the error message that is embedded somewhere deep in the body the returned Error object. It is stored in one of its 100+ attributes. Where should I look for it so I could display in on a screen for the end user to read it?
Then, the err object generated by the try/catch scope has a set of different attributes comparing to the Error object created with new Error("Here is my error message"). Is there a way to normalize the returned Errors so they all have the same or similar attributes?
You don't need to return the whole error object from the server, and arguably shouldn't since error messages can expose internals about your code and infrastructure.
One way you could handle this is to format and return an error message from the server yourself. Assuming you're using express this would look something like:
return res.status(400).json({ message: `The user with email ${email} doesn't exist.` });
Alternatively you could use an error handling middleware like strong-error-handler found here: https://github.com/strongloop/strong-error-handler which automatically builds a json formatted message that's easier to parse, but keep in mind that the content of the message differs depending on whether you set debug mode to true or no.
If you want to develop a secure web application with nice error handling, i will suggest you the following structure.
Step 1. At front end divide your api calls in four main operations for e.g. inset,update,query and filter.
now whenever your page loads and you want to show some data fetched from server then your api call must be like 'https://domainname.tld/server/query' and send some payload with this api call according to need of your data requirements to be fetched.
At backend probably at Server.js handle like this :
app.all("/server/query", function (req, res) {
try {
console.log(a);
// some database or io blocking process
} catch (error) {
// error handling
var err = writeCustomError(error.message || error.errmsg || error.stack);
res.status(417).json(err).end();
}
});
function writeCustomError(message) {
var errorObject = {};
errorObject.message = message;
errorObject.code = 10001; // as you want
errorObject.status = "failed";
return errorObject;
}
in try block you can also handle logical errors using same function i.e writeCustomError
So if you use this approach you can also implement end-to-end encryption and send only eP('encrypted payload') and eK('encryption Key'),by doing this end users and bad end users even can not evaluate your serve API calls.
If you are thinking how will you route different paths at server then simplest solution is send uri in payload from client to server for e.g
User wants to reset password :-
then
call api like this
https://domain.tld/server/execute and send Json object in payload like this {uri:"reset-password",old:"",new:""}.
at backend
use
app.all("/server/execute", function (req, res) {
try {
// decrypt payload
req.url = payload.uri;
next();
} catch (error) {
// error handling
var err = writeCustomError(error.message || error.errmsg || error.stack);
res.status(417).json(err).end();
}
});
app.all("/reset-password", function (req, res) {
try {
// reset logic
} catch (error) {
// error handling
var err = writeCustomError(error.message || error.errmsg || error.stack);
res.status(417).json(err).end();
}
});
so in this way only developer know where password reset logic and how it can called and what parameters are required.
I will also suggest you to create different router files for express like QueryRouter,InsertRouter etc.
Also try to implement end-to-end encryption.Any query regarding post,kindly comment it.
For some reason documents created on my app are not showing up on my remote couchdb database.
I am using the following
import PouchDB from 'pouchdb-react-native'
let company_id = await AsyncStorage.getItem('company_id');
let device_db = new PouchDB(company_id, {auto_compaction: true});
let remote_db = new PouchDB('https://'+API_KEY+'#'+SERVER+'/'+company_id, {ajax: {timeout: 180000}});
device_db.replicate.to(remote_db).then((resp) => {
console.log(JSON.stringify(resp));
console.log("Device to Remote Server - Success");
return resp;
}, (error) => {
console.log("Device to Remote Server - Error");
return false;
});
I get a successful response the response:
{
"ok":true,
"start_time":"2018-05-17T15:19:05.179Z",
"docs_read":0,
"docs_written":0,
"doc_write_failures":0,
"errors":[
],
"last_seq":355,
"status":"complete",
"end_time":"2018-05-17T15:19:05.555Z"
}
When I go to my remote database, document_id's that am able to search and grab on the application do not show up.
Is there something I am not taking into account?
Is there anything I can do to check why this might be happening?
This worked when I used the same scripting method in Ionic and when I switched to React-Native I noticed this is the case.
NOTE: When I do .from() and get data from remote to the device, I get the data. For some reason it just isn't pushing data out
"Is there anything I can do to check why this might be happening?"
I would try switching on debugging as outlined here.
PouchDB.debug.enable('*');
This should allow you to view debug messages in your browser's JavaScript console.
I have a Node.js server which queries MySQL database. It serves as an api end point where it returns JSON and also backend server for my Express application where it returns the retrieved list as an object to the view.
I am looking into implementing flat-cache for increasing the response time. Below is the code snippet.
const flatCache = require('flat-cache');
var cache = flatCache.load('productsCache');
//get all products for the given customer id
router.get('/all/:customer_id', flatCacheMiddleware, function(req, res){
var customerId = req.params.customer_id;
//implemented custom handler for querying
queryHandler.queryRecordsWithParam('select * from products where idCustomers = ? order by CreatedDateTime DESC', customerId, function(err, rows){
if(err) {
res.status(500).send(err.message);
return;
}
res.status(200).send(rows);
});
});
//caching middleware
function flatCacheMiddleware(req, res, next) {
var key = '__express__' + req.originalUrl || req.url;
var cacheContent = cache.getKey(key);
if(cacheContent){
res.send(cacheContent);
} else{
res.sendResponse = res.send;
res.send = (body) => {
cache.setKey(key,body);
cache.save();
res.sendResponse(body)
}
next();
}
}
I ran the node.js server locally and the caching has indeed greatly reduced the response time.
However there are two issues I am facing that I need your help with.
Before putting that flatCacheMiddleware middleware, I received the response in JSON, now when I test, it sends me an HTML. I am not too well versed with JS strict mode (planning to learn it soon), but I am sure the answer lies in the flatCacheMiddleware function.
So what do I modify in the flatCacheMiddleware function so it would send me JSON?
I manually added a new row to the products table for that customer and when I called the end point, it still showed me the old rows. So at what point do I clear the cache?
In a web app it would ideally be when the user logs out, but if I am using this as an api endpoint (or even on webapp there is no guarantee that the user will log out the traditional way), how do I determine if new records have been added and the cache needs to be cleared.
Appreciate the help. If there are any other node.js caching related suggestions you all can give, it would be truly helpful.
I found a solution to the issue by parsing the content to JSON format.
Change line:
res.send(cacheContent);
To:
res.send(JSON.parse(cacheContent));
I created cache 'brute force' invalidation method. Calling clear method will clear both cache file and data stored in memory. You have to call it after db change. You can also try delete specified key using cache.removeKey('key');.
function clear(req, res, next) {
try {
cache.destroy()
} catch (err) {
logger.error(`cache invalidation error ${JSON.stringify(err)}`);
res.status(500).json({
'message' : 'cache invalidation error',
'error' : JSON.stringify(err)
});
} finally {
res.status(200).json({'message' : 'cache invalidated'})
}
}
Notice, that calling the cache.save() function will remove other cached API function. Change it into cache.save(true) will 'prevent the removal of non visited keys' (like mentioned in comment in the flat-cache documentation.
I use the following lib to connect to the cloud controller
https://github.com/prosociallearnEU/cf-nodejs-client
const endpoint = "https://api.mycompany.com/";
const username = "myuser";
const password = "mypass";
const CloudController = new (require("cf-client")).CloudController(endpoint);
const UsersUAA = new (require("cf-client")).UsersUAA;
const Apps = new (require("cf-client")).Apps(endpoint);
CloudController.getInfo().then((result) => {
UsersUAA.setEndPoint(result.authorization_endpoint);
return UsersUAA.login(username, password);
}).then((result) => {
Apps.setToken(result);
return Apps.getApps();
}).then((result) => {
console.log(result);
}).catch((reason) => {
console.error("Error: " + reason);
});
I try to run it against our API and its not working and Im not getting no error message in the console, what it can be ?
where does the space/org is handled here ? since when I connect from the cli it ask me to which space/org I want to connect...
Im able to login via the CLI, just from the code I cant, any idea what is missing here?
The issue it when I run it I dont get any error that can help to understand what is the root cause
I cloned the original git repository and modified some methods to support proxy. Please note that I modified just some methods to get the sample code working, but a complete refactor of the package is needed.
Basically what you have to do is to add a proxy parameter before calling the request method (this is done throughout the package, so several modifications are needed), for example this is for one of the methods in the Organization.js file:
getSummary (guid) {
const url = `${this.API_URL}/v2/organizations/${guid}/summary`;
const proxy = `${this.API_PROXY}`;
const options = {
method: "GET",
url: url,
proxy: proxy,
headers: {
Authorization: `${this.UAA_TOKEN.token_type} ${this.UAA_TOKEN.access_token}`
}
};
return this.REST.request(options, this.HttpStatus.OK, true);
}
You can find my changes in the git repository below:
https://github.com/adasilva70/cf-nodejs-client.git
I have also created a new sample below. This sample lists all organizations for a user, gets the first organization returned and lists its spaces. You can modify the code to provide a similar functionality that cf login provides (allow you to select an organization then a space).
const endpoint = "https://api.mycompany.com/";
const username = "youruser";
const password = "yourpassword";
const proxy = "http://proxy.mycompany.com:8080";
const CloudController = new (require("cf-nodejs-client")).CloudController(endpoint, proxy);
const UsersUAA = new (require("cf-nodejs-client")).UsersUAA;
const Apps = new (require("cf-nodejs-client")).Apps(endpoint, proxy);
const Orgs = new (require("cf-nodejs-client")).Organizations(endpoint, proxy);
CloudController.getInfo().then((result) => {
console.log(result);
UsersUAA.setEndPoint(result.authorization_endpoint, proxy);
return UsersUAA.login(username, password);
}).then((result) => {
//Apps.setToken(result);
//return Apps.getApps();
Orgs.setToken(result);
return Orgs.getOrganizations();
}).then((result) => {
console.log(result);
org_guid = result.resources[1].metadata.guid;
return Orgs.getSummary(org_guid);
}).then((result) => {
console.log(result);
}).catch((reason) => {
console.error("Error: " + reason);
});
I have done just minor tests to make sure the sample works, so use carefully. Also, the changes will only work for a case where proxy is needed now.
The first thing that strikes me on the library's github site is the warning:
Note: This package is not ready for a production App yet.
It also seems that the project is not being maintained as there are a number of tickets ooened that are quite a few months old that don't have a response.
Anyway, to figure out why the library is not working and producing no error message, I would check out the library source code and add some console logging statements, probably starting with the HttpUtils. For example:
requestWithDefaults(options, function (error, response, body) {
console.log("requestWithDefaults error: ", error)
console.log("requestWithDefaults response: ", response)
console.log("requestWithDefaults body: ", body)
...
}
Alternatively, you could try debugging the code by adding breakpoints to the requestWithDefaults and other key places in the library, using the nodejs debugger.
You could also try debugging the network calls similar to this how to monitor the network on node.js similar to chrome/firefox developer tools?
To understand how to use the library, I would take a look into the tests folder and look for a test that is similar to your use case. There are a reasonable amount if tests that look useful in the test/lib/model/cloudcontroller folder.
As for the question about spaces, I have found an example where you can pass in a space guid to return apps for that space guid.
CloudFoundrySpaces.getSpaceApps(space_guid, filter).then( ... )
I'm assuming the call you are using App.getApps() will return Apps for all spaces/organizations.
I've got some data from a JSON file, which I use in my HTML getting it first from AngularJS like this:
$http.get('js/data.json').success(function(data) {
$scope.data = data;
});
And I want to update this JSON file after clicking a button in the HTML:
<button ng-click="postData(id)">Post</button>
You cannot write on files via JavaScript only (AngularJS).
You are to go via server side and point your "post" request to a server side script (i.e: PHP) and make that script do the job.
This sort of thing won't work. The file you are trying to write to would be on a server; and as it is right now, it would be a static resource. I'd suggest reading up on Angular resources, here. You can set up your server-side code to perform CRUD operations on the json file, but an actually database would be best. If you prefer to use a json format, Mongodb is your best choice; here is a link to Mongodb University, which offers free courses. I've done it in the past, and it's been great.
Now, for some actually help in your situation:
You can perform a GET request on your json file because it's seen as a static resource. The POST request, however, needs server-side scripting to do anything.
$http.get('api/YOUR_RESOURCE').success(function(data) {
$scope.database = data;
});
$http.post('api/YOUR_RESOURCE', {
data_key: data_value,
data_key2: data_value2
}).success(function(data) {
data[id].available = false;
});
This may be further ahead on your path to learning Angular, but here is a snippet of Node.js server code, with a Mongo database and Mongoose to handle the 'Schema', to help you get an idea of how this works:
var mongoose = require('mongoose'),
YOUR_RESOURCE = mongoose.model('YOUR_RESOURCE');
app.route('/api/YOUR_RESOURCE')
// This should be your GET request; 'api/
.get(
// Get all docs in resource
YOUR_RESOURCE.find().exec(function (err, data) {
if (err) {
return res.status(400).send({
message: SOME_ERROR_HANDLER
});
} else {
res.json(data); // return list of all docs found
}
});)
// Add new doc to database
.post(function (req, res) {
// The keys of the object sent from your Angular app should match
// those of the model
var your_resource = new YOUR_RESOURCE(req.body);
your_resource.save(function (err) {
if (err) {
return res.status(400).send({
message: SOME_ERROR_HANDLER
});
} else {
// returns newly created doc to Angular after successful save
res.json(your_resource);
}
});
);
Here is an SO page with a list of resources on getting started with Node; I recommend Node because of it's ease of use and the fact that it is written in JS. The Mongo University lessons also go through setting up you server for use with the database; you can choose between several flavors, such as Java, .NET, Python or Node.
There is a bit left out in the examples above, such as the Mongoose model and Node setup, but those will be covered in the resources I've linked to on the page, if you choose to read them. Hope this helps :)