How to Access Email OR Contacts from Gmail or Google using Asp.net.
Hi, I was trying to get
email list of a particular user from gmail using Oauth to invite friends in my
recent project.
Now Question is How
to Access Email or Contacts from Gmail or Google. So,we will access email or contacts from google
contacts in ASP.NET page.
So implementation of Google Contact Api with oauth read following steps.
First we have to create an
account with google. Then, access the google developer console.https://console.developers.
Create a project
Note: We will Access email list using OAuth of
google. For more information on this topic you can click on the following link: https://developers.google.com/google-apps/contacts/v3/
Enable the Contact
API
Browse Contact API
in Browse API text box and change status as ON.
Create New client ID
Click on APIs & auth in left side tab, then click on Credentials menu and create new
client ID.
Now our setup is ready for use API.
Now we have to hit an http
request to authenticate the google user and get permission to access contact
list.
Following code will hit
the request to authenticate user for getting permission to access the contact
list.
string AppClientID="xxxxxxxxxxx.apps.googleusercontent.com";
string AppRedirectURL="http://localhost:50485/Default.aspx";
Response.Redirect("https://accounts.google.com/o/oauth2/auth?" +"client_id=" + AppClientID + "&" +"redirect_uri=" + HttpUtility.UrlEncode(AppRedirectURL) + "&" +"scope=" + HttpUtility.UrlEncode("https://www.googleapis.com/auth/contacts.readonly") + "&" +"response_type=code");
After authenticating the
user, google api redirect to a particular page, that we had already setup.
(string AppRedirectURL="http://localhost:50485/Default.aspx";)
And when it will redirect,
you will get an authentication code within a query string with parameter name
code. We have to handle that
response.
after we receive the code
we will hit another request and along with this request we will include the
received code. If the code matches, we will get an access token.
string AppClientID="xxxxxxxxxxxxxxxxxx.apps.googleusercontent.com";//put your app id
string AppClientSecret = "xxxxxxxxxxxxxxxx";//put your app secret
string AppRedirectURL = "http://localhost:50485/Default.aspx";
if
(Request.QueryString["code"]
!= null && Request.QueryString["error"]
!= "access_denied")
{
WebRequest
requestLogIn = null;
Stream
stream = null;
WebResponse
response = null;
StreamReader
reader = null;
string
sendData = "code=" +
Request.QueryString["code"]
+ "&";
sendData += "client_id="
+ AppClientID + "&";
sendData += "client_secret="
+ AppClientSecret + "&";
sendData += "redirect_uri="
+ AppRedirectURL + "&";
sendData += "grant_type=authorization_code";
requestLogIn= WebRequest.Create("https://accounts.google.com/o/oauth2/token");
requestLogIn.Method = "POST";
requestLogIn.ContentType = "application/x-www-form-urlencoded";
byte[]
arrayToSend = Encoding.UTF8.GetBytes(sendData);
requestLogIn.ContentLength =
arrayToSend.Length;
stream =
requestLogIn.GetRequestStream();
stream.Write(arrayToSend, 0,
arrayToSend.Length);
stream.Close();
if
(((HttpWebResponse)response).StatusCode == HttpStatusCode.OK)
{
stream =
response.GetResponseStream();
reader = new StreamReader(stream);
responseValue =
reader.ReadToEnd();
reader.Close();
varlJSONResponse = new JavaScriptSerializer().Deserialize<JSONResponseToken>(responseValue);
}
}
For Deserialize
the response value we have to create a class following.
class JSONResponseToken
{
public string
Access_Token { get; set;
}
}
Now we will hit api
request for google email. and in its header we will pass the access_Token and
in return we will receive the emails list.
WebRequest
myRequest = WebRequest.Create("https://www.google.com/m8/feeds/contacts/default/full?max-results=1000");
myRequest.Method = "GET";
myRequest.Headers.Add("Authorization",
"Bearer " +
lJSONResponse.Access_Token);
response =
myRequest.GetResponse();
if
(((HttpWebResponse)response).StatusCode == HttpStatusCode.OK)
{
stream =
response.GetResponseStream();
reader = new StreamReader(stream);
responseValue = reader.ReadToEnd();
}
Now finally we get the
response in a particular format that we had setup in our api request.(by
default its xml)
Now it’s done. We have to
parse that response and print or use the emails.
after implementation of code output will be look like follow.
I hope its help you, if have need any kind of help then you
can email or comments.
