DNS Lookup for localhsot failed. No such host is known - wcf

i did a break point on the method but it never goes there and also if paste the url in the web browser and hit enter and this is what i get in Firebug:
ReadResponse() failed: The server did not return a response for this request.
EDIT:
indeed that was typo, after correcting it and i still have no response, in FF i see the response
GET GetCustomer?method=jsonp1299253547713
http://localhost:2344/service1.svc/GetCustomer?method=jsonp1299253547713
Aborted
localhost:2344
?
what may be wrong ?
END EDIT
i have a created wcf services using json with padding (http://msdn.microsoft.com/en-us/library/cc716898(v=vs.90).aspx)
i have the code below that i am using to call the service, and this code is in html page withint th same project that i have created the wcf service.
$("#btn").click(function (event) {
$.getJSON('http://localhsot:2344/Service1.svc/GetCurrentUser?method=?', { },
function (data) {
debugger
alert(data);
});
//return false;
});
getting this error:
DNS Lookup for localhsot failed. No such host is known

Try renaming:
localhsot => localhost

You spelled localhost wrong. Look at your url and fix the spelling error.

Related

API GET request URL works on Brave/Chrome but not on fetch()

When I paste and search this url
https://api.openweathermap.org/data/2.5/forecast?lat=39.48923&lon=-0.4780256&appid=b11fc49d6b14456d6aacedc8d0153072
it makes the request just fine:
But then on my code, when I want to fetch it and save this json it turns out with "Network request failed":
I have only used fetch() with local urls and it always worked.
This is my code (you can use my api key I can generate a new one later):
GetClima() {
//fetch(`${this.state.api.url}lat=${this.props.latitudDestino}&lon=${this.props.longitudDestino}&appid=${this.state.api.key}`)
fetch("https://api.openweathermap.org/data/2.5/forecast?lat=39.48923&lon=-0.4780256&appid=b11fc49d6b14456d6aacedc8d0153072")
.then(res => res.json())
.then(res => {
this.setState({
dataClima: res
})
})
}
This is because your emulator/simulator isn't connected to the internet. I can see your Wi-Fi icon in the status bar saying that it isn't connected to the internet.
It clearly says Type Error: Network Request Failed. Make sure that you have configured your virtual device properly and check your internet connection.
Having that said, make sure that you catch the errors properly using .catch() or using try-catch block if you're using async-await

webpack dev-server: Avoid proxy errors on HTTP errors returned from proxy target

I have a Vue.js project where I have configured a webpack dev-server to proxy all requests to the UI to my backend server. Here is the relevant part of vue.config.js:
devServer: {
contentBase: PATHS.build,
port: 9000,
https: false,
hot: true,
progress: true,
inline: true,
watchContentBase: true,
proxy: {
'^/': {
target: 'http://127.0.0.1:8089',
secure: false
},
}
},
I've noticed that if the HTTP response code from http://127.0.0.1:8089 is anything other than 2xx then the proxy fails with the following error:
Proxy error: Could not proxy request /api/test from localhost:9000 to http://127.0.0.1:8089.
See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (HPE_INVALID_CHUNK_SIZE).
This also causes the HTTP response code from the request to localhost:9000 to be 500 for any error and all the information about what went wrong on the server side is lost. This is problematic as I want to be able to extract information from error responses to display to the user.
I know it's possible to do because I had it working on an older Angular project which I think was using Webpack 3 (am now using Webpack 4). I tried copying all the dev-server config from this project but it just doesn't seem to work here!
EDIT: I was wrong. The Proxy error does not occur on every bad response but only for one of the requests which is a multipart file upload. Still unable to reproduce this in a smaller example to put on github though so struggling to pinpoint the cause.
This error message comes from node_modules/#vue/cli-service/lib/util/prepareProxy.js, which define a onError callback for node-http-proxy;
So I did some experiment, make back-end api generate 400 404 500 response, but I didn't got this error.
After I happen to close back-end api, error arise:
Proxy error: Could not proxy request /hello from localhost:8080 to http://localhost:8081 (ECONNREFUSED).
I search in the doc and find these:
The error event is emitted if the request to the target fail. We do not do any error handling of messages passed between client and proxy, and messages passed between proxy and target, so it is recommended that you listen on errors and handle them
So the onError do not handle error code, is called only when request fail (500 response is still treated as a complete request, connection refuse is not)
Go back to your error message, [HPE_INVALID_CHUNK_SIZE] means bad request to the back-end api. In this issue, it gives an solution: add a keep-alive header:
devServer: {
publicPath: 'http://localhost:9090/front/static-dev/build/',
port: 9090,
proxy: {
'/**': {
target: 'http://localhost:8080',
secure: false,
changeOrigin: true,
headers: {
Connection: 'keep-alive'
}
},
open: true
}
I have finally found the problem, and I apologise, it was a lot more of a specific issue than I originally thought when I wrote the question.
Issue was to do with a request which was proxied to another server using the Spring RestTemplate:
e.g.
#PostMapping("/upload")
public ResponseEntity upload(#RequestParam("file") MultipartFile file)
throws Exception {
String baseUrl = serviceProperties.getAddress();
HttpEntity<MultiValueMap<String, Object>> request = createMultipartRequest(file.getBytes());
return restTemplate.postForEntity(baseUrl + "/api/upload", filterRequest, String.class);
}
The ResponseEntity returning from the rest template proxy contained the header "Connection: close" when the response was anything other than 200 which cause the connection to close and caused this request to fail to return anything which subsequently made the dev-server proxy fail on the UI.
Fixed this by not passing the response headers from the rest template proxy to the response:
#PostMapping("/upload")
public ResponseEntity upload(#RequestParam("file") MultipartFile file)
throws Exception {
String baseUrl = serviceProperties.getAddress();
HttpEntity<MultiValueMap<String, Object>> request = createMultipartRequest(file.getBytes());
ResponseEntity response = restTemplate.postForEntity(baseUrl + "/api/upload", filterRequest, String.class);
return new ResponseEntity<>(response.getBody(), response.getStatusCode());
}

react-apollo Error: Network error: Unexpected token < in JSON at position 1

I want to send a request to this server via Apollo and get a query :
const client = new ApolloClient({
link: new HttpLink({
uri:'http://mfapat.com/graphql/mfaapp/'}),
cache: new InMemoryCache()
})
const FeedQuery = gql
query{
allFmr{
fmrId,
name,
studio,
bedRm1,
bedRm2,
bedRm3,
bedRm4
}
}
`
But I'm facing this error message:
Unhandled (in react-apollo:Apollo(FMRScreen)) Error: Network error: Unexpected token < in JSON at position 1
at new ApolloError (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:109336:32)
at ObservableQuery.currentResult (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:109447:28)
at GraphQL.dataForChild (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:103192:66)
at GraphQL.render (http://localhost:8081/index.bundle?platform=android&dev=true&minify=false:103243:37)
....
But I can easily open "http://mfapat.com/graphql/mfaapp/" in my browser and get a query. Does anyone know where the problem is?
Right now, Apollo treats everything sent from the server as JSON. However, if there is an error, then your server might be sending HTML to show a basic error page.
To see the error, open your dev tools, and look at the network tab. This shows an example 401 error:
As you can see, if you were to parse this as JSON you would stumble over the first character: < which is where our error message comes from.
Reading the specific error sent enables you to fix the bug.
To fix the general error, configure your server to send JSON on HTTP errors, not HTML code. This should allow Apollo to parse it and display a sensible error page.
EDIT: Also see this discussion - hopefully they will change the default Apollo behavior, or at least provide useful discussion.
Base on #eedrah answer, I managed to resolve this issue by using an error handler middleware to always return erros as JSONs, so that Apollo Client error link can parse the errors.
// On Apollo server
// Error handler
const errorHandler = (err, req, res, next) => {
if (res.headersSent) {
return next(err);
}
const { status } = err;
res.status(status).json(err);
};
app.use(errorHandler);

electron certificates network

I am trying to write a simple electron app to interface with a REST server. The server doesn't have the appropriate certificates. When I try to make a 'GET' request (using fetch()), I get the following error message:
Failed to load resource: net::ERR_BAD_SSL_CLIENT_AUTH_CERT
Fixing the certs is not currently an option. I tried to use the 'ignore-certificates-error' flag (see below). It seems like it should allow me to skip over this error, but it doesn't.
var electron = require('electron');
var app = electron.app
app.commandLine.appendSwitch('ignore-certificate-errors');
...
The result is the same error.
Questions:
I am correct in assuming this options is supposed to help here?
If so, any ideas what I am doing wrong?
Electron version: 1.2.8
Thanks!
You can update your version of electron and use this callback:
app.on('certificate-error', (event, webContents, link, error, certificate, callback) => {
if ('yourURL/api/'.indexOf(link) !== -1) {
// Verification logic.
event.preventDefault();
callback(true);
} else {
callback(false);
}
});
That you going do the fetch to your api with https.

jQuery .ajax call returning error when accessing Java Spring service via domain name based URL

My application's HTML5, jQuery Mobile frontend talks to Java server (Spring, Hibernate, MySQL). The application works fine on my notebook as well as in QA environment. On QA, I'm accessing the application using the server's IP address.
When I host the application in Live environment (the same server as QA but a different web app in Tomcat) and try to access it using URL with the domain name, $.ajax calls in the application return error.
One of the calls is as follows:
$.ajax({
type : "GET",
url : "http://www.smartcloudlearning.mobi:9080/SmartCloudLearningMobi/rest/resource/getResourceTypes",
cache : false,
async : false,
dataType : 'json',
success : function(rTypes) {
Alert("success!");
},
error : function(XMLHttpRequest, textStatus, errorThrown) {
alert("An error has occurred making the request: " + errorThrown);
}
});
I get the following error in Firefox:
An error has occurred making the request: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE)" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: http://www.smartcloudlearning.mobi/js/jquery-1.7.1.min.js :: <TOP_LEVEL> :: line 4" data: no]
I get the following error in Chrome:
An error has occurred making the request: Error: NETWORK_ERR: XMLHttpRequest: Exception 101
In the server log, I see that the requested Spring service was successfully invoked but it looks like the client doesn't receive the data!
If I hit the URL
http://www.smartcloudlearning.mobi:9080/SmartCloudLearningMobi/rest/resource/getResourceTypes
directly in the browser, I get expected results! I sense that this is somehow due to how I forward server request from Apache to Tomcat.
The following are the lines in Apache / httpd server's httpd.conf file:
ProxyPass /SmartCloudLearningMobi http://www.smartcloudlearning.mobi:9080/SmartCloudLearningMobi
ProxyPassReverse /SmartCloudLearningMobi http://www.smartcloudlearning.mobi:9080/SmartCloudLearningMobi
Can anyone tell me what's amiss here? Much appreciated!
I managed to solve the problem:
The browser was giving the error on .ajax call because I had port number in my URL. The port number got carried over when I created 'live' URL from my QA URL. When I removed the port number from the .ajax call's URL, the call started returning success!
Jason Foglia, your statement "... and also the port..." nudged me to explore that angle... thanks a lot!
You're probably getting an error because of a security concept called "same origin policy" which doesn't allow you to call a service from a different domain. Or at least, disallow you from calling a method in that service.
Same discussion is found here - AJAX Cross Domain
You can however implement a cross-domain using JSONP - Wikipedia on JSONP
The solution is to change the datatype to JSONP:
$.ajax({
url:"http://www.smartcloudlearning.mobi:9080/SmartCloudLearningMobi...",
dataType: 'jsonp',
...
});
Try using an relative url:
If that doesn't work is the domain name the same as the url and also the port.
Browsers don't allow cross domains.
$.ajax({
type : "GET",
url : "/SmartCloudLearningMobi/rest/resource/getResourceTypes",
cache : false,
async : false,
contentType : "application/json"
dataType : 'json',
success : function(rTypes) {
Alert("success!);
},
error : function(XMLHttpRequest, textStatus, errorThrown) {
alert("An error has occurred making the request: " + errorThrown);
}
});
The browser was giving the error on .ajax call because I had port number in my URL. The port number got carried over when I created 'live' URL from my QA URL. When I removed the port number from the .ajax call's URL, the call started returning success!
Jason Foglia, your statement "... and also the port..." nudged me to explore that angle... thanks a lot!