Salesforce Google drive integration | Upload files from Salesforce to Google drive

Follow the below steps for the integration of Salesforce and Google drive (to select files from local and upload to Google drive using Salesforce code):

1. Open Google Drive console. Here is the link for console:
https://console.developers.google.com/apis

2. Select a project. If you don’t have any project then create one.

3. Click on Drive API:

4. Click on Create Credentials:

5. Generate API key and Client Secret.

6. Use key and client secret in your apex class to get access token.

7. Enable Google apis.

Create a visualforce page for browsing a file from your local system and uploading it to google drive.

Sample code of the visualforce page with CSS:

<apex:page controller="GoogleDriveController">
<style>
.error {
font-style: italic;
font-size: 15px;
font-weight: bold;
text-align: center;
color: green;
}

.myClass {
color: black !important;
background: #145a32 !important;
width: 300px;
font-size: 20px !important;
height: 35px;
}
</style>
<center>
<apex:form style="margin-top:5%;margin-left:5%;width:60%">
<apex:pageblock>
<apex:commandbutton styleClass="myClass" onclick="this.value = 'Authenticating....'" action="{!DriveAuth}" value="Google Drive Authentication">
</apex:commandbutton>
<br/>
<br/>
<br/>
<br/>
<apex:inputfile value="{!file}" contentType="{!filetype}" filename="{!filename}" />
<br/>
<br/>
<br/>
<br/>
<apex:commandButton styleClass="myClass" onclick="this.value = 'Uploading...'" value="Upload file" action="{!UploadFile}" />
<br/>
<br/>
<apex:messages styleClass="error" />
<br/>
</apex:pageblock>
</apex:pageblock>
</apex:form>
</center>
</apex:page>

Click on Google Drive Authentication button then browse your file and finally upload that file.

Create an apex class for the above visualforce page for uploading a file to google drive.

Sample code of apex class:

public class GoogleDriveController {
private String code;

public boolean val {
    get;
    set;
    }

public blob file {
    get;
    set;
    }

public String filetype {
    get;
    set;
    }
   
public String filename {
    get;
    set;
    }
private string key = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
private string secret = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
private string redirect_uri = 'https://xxxxxxxxxxxxxxx.force.com/apex/GoogleDrive';
private String accesstoken;
private Integer expiresIn;
private String tokentype;
public GoogleDriveController() {
code = ApexPages.currentPage().getParameters().get('code');
//Get the access token once we have code
if (code != '' & amp; & amp; code != null) {
AccessToken();
 }
}
public PageReference DriveAuth() {
//Authenticating
PageReference pg = new PageReference(GoogleDriveAuthUri(key, redirect_uri));
return pg;
}

public String GoogleDriveAuthUri(String Clientkey, String redirect_uri) {
String key = EncodingUtil.urlEncode(Clientkey, 'UTF-8');
String uri = EncodingUtil.urlEncode(redirect_uri, 'UTF-8');
String authuri = '';
authuri = 'https://accounts.google.com/o/oauth2/auth?' +
      'client_id=' + key +
      '&response_type=code' +
      '&scope=https://www.googleapis.com/auth/drive' +
      '&redirect_uri=' + uri +
      '&state=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' +
       +
      'access_type=offline';
       return authuri;
    }
public void UploadFile() {
String boundary = '----------9889464542212';
String delimiter = '\r\n--' + boundary + '\r\n';
String close_delim = '\r\n--' + boundary + '--';
String bodyEncoded = EncodingUtil.base64Encode(file);
String body = delimiter + 'Content-Type: application/json\r\n\r\n' + '{ "title" : "' + filename + '",' + ' "mimeType" : "' + filetype + '" }' + delimiter + 'Content-Type: ' + filetype + '\r\n' + 'Content-Transfer-Encoding: base64\r\n' + '\r\n' + bodyEncoded + close_delim;
Http http = new Http();
HttpRequest req = new HttpRequest();
req.setEndpoint('https://www.googleapis.com/upload/drive/v2/files?uploadType=multipart');
req.setHeader('Authorization', 'Bearer ' + accessToken);
req.setHeader('Content-Type', 'multipart/mixed; boundary="' + boundary + '"');
req.setHeader('Content-length', String.valueOf(body.length()));
req.setBody(body);
req.setMethod('POST');
req.setTimeout(60 * 1000);
HttpResponse resp = http.send(req);
file = null;
filetype = '';
filename = '';
}
public void AccessToken() {
//Getting access token from google
HttpRequest req = new HttpRequest();
req.setMethod('POST');
req.setEndpoint('https://accounts.google.com/o/oauth2/token');
req.setHeader('content-type', 'application/x-www-form-urlencoded');
String messageBody = 'code=' + code + '&client_id=' + key + '&client_secret=' + secret + '&redirect_uri=' + redirect_uri + '&grant_type=authorization_code';
req.setHeader('Content-length', String.valueOf(messageBody.length()));
req.setBody(messageBody);
req.setTimeout(60 * 1000);
Http h = new Http();
String resp;
HttpResponse res = h.send(req);
resp = res.getBody();
JSONParser parser = JSON.createParser(resp);
while (parser.nextToken() != null) {
    if ((parser.getCurrentToken() == JSONToken.FIELD_NAME)) {
    String fieldName = parser.getText();
    parser.nextToken();
    if (fieldName == 'access_token') {
    accesstoken = parser.getText();
    } else if (fieldName == 'expires_in') {
     expiresIn = parser.getIntegerValue();
    } else if (fieldname == 'token_type') {
     tokentype = parser.getText();
    }
 } }
 System.debug(' You can parse the response to get the access token ::: ' + resp);
    }
}