What is CORS in Angular?
It is a security feature implemented in web browsers to prevent malicious websites from interacting with resources on a different domain (or origin) without explicit permission.
An origin defined and combination of:
- Protocol( HTTP, HTTPS)
- HostName(example.com)
- Port(eg: 8080, 8024)
Access to XMLHttpRequest at
'http://api.example.com'
from origin
'http://localhost:4200'
has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Allowed by Same-Origin Policy:
http://example.com/page → http://example.com/api
Blocked by Same-Origin Policy:
http://example.com/page → http://api.example.com/data
Reach out to the API provider to ask them to enable CORS for your origin.
If you cannot modify the server:- Use a proxy server to forward your requests. The proxy will make the request to thetarget server and return the response, bypassing the CORS restriction.
- Browser Extensions (Temporary Development Use)
Use a browser extension like CORS Unblock or Allow-Control-Allow-Origin to disable CORS during development.
- Note: This is not recommended for production as it compromises security. Best Practice For production environments, always aim to fix CORS issues on the server side to ensure proper security practices are in place.
Sol:1
->Angular provides tools like HttpClient and proxy configurations to facilitate communication with APIs.
Api url => https://freeapi.miniprojectideas.com/api/Jira/GetAllUsers
proxy.conf.json
{
"/api": {
"target": "https://freeapi.example.com",
"secure": false,
"changeOrigin": true,
"pathRewrite": {
"^/api": "/api"
}
}
}
Explanation:
/api": The proxy path you will use in your frontend code. Any API calls to /api will be forwarded to the specified target.
target": The base URL of the API server.
secure": If the server uses HTTPS with an invalid or self-signed certificate, set this to false.
changeOrigin": Ensures the Host header in the proxied request matches the target URL.
logLevel": Set to debug during development to help you debug proxy issues.
angular.json
"architect": {
"serve": {
"options": {
"proxyConfig": "src/proxy.conf.json"
}
}
}
Service File : Api url update
export class MasterService {
constructor(private http:HttpClient) {}
loginUser(objs:any){
return this.http.post("/api/User/Login",objs)
}
}
Confirm that the request URL is proxied as
http://localhost:4200/api/Jira/GetAllUsers but forwarded to
https://freeapi.miniprojectideas.com/api/Jira/GetAllUsers
Sol:2
- Service file through we can also handle cross-origin policy.
- Service file is used to encapsulate and manage logic, such as making HTTP requests to fetch or send data from/to a backend API.
- You can create a service file in Angular to fetch data while dealing with cross-origin policies effectively.
httpOptions = {
headers: new HttpHeaders({
'Content-Type': 'application/json',
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Credentials': 'true',
'Access-Control-Allow-Headers': 'Content-Type',
'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE',
// "authorization":'Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOnsiaWQiOjQyNDEsInJvbGUiOiJBZG1pblRlc3QiLCJwYXJlbnRfaWQiOiI0MjM4LDQyMzIsNDIyOSwxIiwidXNlcl90eXBlX2lkIjo1fSwiaWF0IjoxNjEwNjAxNTM5fQ.02Lv9P48SFmxsMEBr8X2vYBTdBi5vZpYh9ZfPBi7kio'
})
};
headers: new HttpHeaders({
'Content-Type': 'application/json',
'Access-Control-Allow-Origin': '*',
'Access-Control-Allow-Credentials': 'true',
'Access-Control-Allow-Headers': 'Content-Type',
'Access-Control-Allow-Methods': 'GET,PUT,POST,DELETE',
// "authorization":'Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOnsiaWQiOjQyNDEsInJvbGUiOiJBZG1pblRlc3QiLCJwYXJlbnRfaWQiOiI0MjM4LDQyMzIsNDIyOSwxIiwidXNlcl90eXBlX2lkIjo1fSwiaWF0IjoxNjEwNjAxNTM5fQ.02Lv9P48SFmxsMEBr8X2vYBTdBi5vZpYh9ZfPBi7kio'
})
};
Sol:3
=>Use Angular HTTP Interceptors for Custom Headers
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