Custom Function - GetFileMimeType

[ehmd]

Custom Function to get a files MimeType.
Useful to check any uploaded files are of the correct file type and matches the file extension. e.g. to stop someone renaming an executable file as a .jpg

Code: Select all

package com.ebasetech.ufs.customfunctions; 

import java.util.*;
import org.nfunk.jep.*;
import com.ebasetech.ufs.function.*;
import com.ebasetech.ufs.kernel.*;
import java.io.File;
import org.apache.tika.Tika;
import org.apache.tika.detect.DefaultDetector;
import org.apache.tika.detect.Detector;
import org.apache.tika.io.TikaInputStream;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MimeTypes;

public class GetFileMimeType extends UFSCustomFunction {

    public GetFileMimeType (UFSFormInterface formInterface) {
	super(formInterface);

        /* Specify the number of parameters to be received by the custom function */

	numberOfParameters = 1;
	}

    public void run(Stack inStack) throws ParseException {

        boolean fileExists = false;
        String mimeType = null;
        
        Object param1 = inStack.pop();

		if ( param1 instanceof String ) {
            
                String fileName = param1.toString();
                
                if ( fileName.length() == 0) {
                        inStack.push(new String("ERROR"));
                        return;                        
                }
                
                try {
                    fileExists = (new File(fileName)).exists();
                    if ( fileExists ) {
                        
                        File f = new File(fileName);
                        
                        Tika tika = null;
                        TikaInputStream is = null;
	 
                        // Creating new Instance of org.apache.tika.Tika
                        tika = new Tika();
	 
                        // Detecting MIME Type of the File
                        mimeType = tika.detect(f);
                        
                        inStack.push(new String(mimeType));
                        return;                        
                        
                        
                    } else {
                        inStack.push(new String("NOFILE"));
                        return;
                    }
                    
                } catch ( Exception e ) {
                    inStack.push(new String("ERROR"));
                    return;                   
                } 
                
        } else {
                inStack.push(new String("ERROR"));
                return;             
        }

        
    }

    
}

Uses Apache Tika from http://tika.apache.org

[Jon]

Here is the corresponding function written in Javascript:

Code: Select all

function getMimeTypeForFile(path)
{
	var f = new java.io.File(path);
	if (f.exists())
	{
		var tika = new org.apache.tika.Tika();
		return tika.detect(f);
	}
	return null;
}

Note to do this, you need to add the apache tika jar file to WEB-INF/lib on the server.

With Java 1.7, this can be done more easily (i.e. without apache tika) using the Files.probeContentType() method.

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