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Check if a document exists in a Sharepoint library Tag(s): Networking


To check if a document is present in a Sharepoint library, we are using the REST API provided by Microsoft. All we need is the Apache HttpComponents library to make the call.

If you are using Maven, here is the POM 

    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.3.5</version>
    </dependency>

To check if a document exists or not, we try to get its Etag (Entity-tag).

import org.apache.http.HttpHost;
import org.apache.http.HttpStatus;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.NTCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpDocumentExistsWithHttpClient {
  /**
   * check if a document exists in a sharepoint library
   */
   public static void main(String[] args) throws Exception{
     CloseableHttpClient httpclient = HttpClients.custom()
      .setRetryHandler(new DefaultHttpRequestRetryHandler(0,false))
      .build();

     String user = "myusername";
     String pwd = "mypassword";
     CredentialsProvider credsProvider = new BasicCredentialsProvider();
     credsProvider.setCredentials(AuthScope.ANY,
        new NTCredentials(user, pwd, "", ""));
     // You may get 401 if you go through a load-balancer.
     // To fix this, go directly to one of the sharepoint web server or
     // change the config. See this article :
     // http://blog.crsw.com/2008/10/14/unauthorized-401-1-exception-calling-web-services-in-sharepoint/
     HttpHost target = new HttpHost("web01.mysharepoint.local", 80, "http");
     HttpClientContext context = HttpClientContext.create();
     context.setCredentialsProvider(credsProvider);

     // The authentication is NTLM.
     // To trigger it, we send a minimal http request
     HttpHead request1 = new HttpHead("/");
     CloseableHttpResponse response1 = null;
     try {
       response1 = httpclient.execute(target, request1, context);
       EntityUtils.consume(response1.getEntity());
       System.out.println("1 : " + response1.getStatusLine().getStatusCode());
     }

     finally {
       if (response1 != null ) response1.close();
     }

     // The real request, reuse authentication
     String file = "/30500C/PubDoc/TEST/jira.log";  // source
     HttpGet request2 = new HttpGet("/_api/web/GetFileByServerRelativeUrl('" + file + "')/Etag");
     CloseableHttpResponse response2 = null;
     try {
       response2 = httpclient.execute(target, request2, context);
       EntityUtils.consume(response2.getEntity());
       int rc = response2.getStatusLine().getStatusCode();
       String reason = response2.getStatusLine().getReasonPhrase();
       if (rc != HttpStatus.SC_OK) {
         System.out.println(file + " is missing.  Reason : "
             + reason + "   rc : " + rc + "(500 is the equivalent of NOT FOUND)");
       }
       else {
         System.out.println(file + " exists.");
       }
     }
     finally {
       if (response2 != null) response2.close();
     }
     return;
   }
}
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