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Posts Tagged ‘ pdf ’

Request Mocking to use groovyPagesTemplateEngine in backend threads

Posted by Vivek Krishna on December 27th, 2010

We have a setup where a backend thread, fired by the Spring Events, does some processing, generates a PDF and emails the result to the user.
The code we were using to generate the HTML from a GSP to be converted to a PDF using iText was as follows :

        def webRequest = RequestContextHolder.getRequestAttributes()
        def originalOut = webRequest.out
        try {
            def sw = new StringWriter()
            def pw = new PrintWriter(sw)
            webRequest.out = pw
            groovyPagesTemplateEngine.createTemplate("path_to_gsp").make([model:model]).writeTo(pw)
            return sw.toString()
        } finally {
          webRequest.out = originalOut
        }

There was the obvious fallibility of this code that there was no Current Request associated with the backend thread!

After doing some googling around it, I came across a few threads and posts which talked about Request Mocking, which has been used in Grails Template Engine Plugin.  We overcame this by using the code snippet given below to mock the web request

def webRequest = RequestContextHolder.getRequestAttributes()
if(!webRequest) {
          def servletContext  = ServletContextHolder.getServletContext()
          def applicationContext = WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext)
          webRequest = grails.util.GrailsWebUtil.bindMockWebRequest(applicationContext)
}

However, things didn’t end there. This code broke while working on a WAR environment. The problem was that the MockWebRequest class was part of the “org.springframework:org.springframework.test:3.0.3.RELEASE” jar and had to be included in the BuildConfig.groovy as


dependencies{

runtime 'org.springframework:org.springframework.test:3.0.3.RELEASE'

}

Ensure that the line


mavenCentral()

is not commented in BuildConfig.groovy

We were working on Grails 1.3.4

 

Hope this helps.
Vivek

http://in.linkedin.com/in/svivekkrishna

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Using iText PdfStamper to insert Images in PDFs while preserving Acroforms

Posted by Vivek Krishna on November 29th, 2010

We had a requirement that a template PDF which had Acroform fields had to be pre-populated (like name, email id etc) and sent to the end user so that he/she only needed to fill in the details which were expected to be filled by him/her.

After going through the iText library, we found that the PdfStamper class was the best way to go about it. However, we also discovered that we needed to embed a data matrix image in the document so that it can be identified by scanning the printed version of the document which is received back from the end user. After pondering on how to do it, we stumbled across this page. This was the perfect solution we were looking for.

Our service method looked something like

def populateFieldsAndSetImage(byte[] pdf){
        PdfReader reader = new PdfReader(pdf)
        ByteArrayOutputStream output = new ByteArrayOutputStream()
        def stamper = new PdfStamper(reader, output)
        AcroFields form= stamper.getAcroFields()
        form.setField('Address', 'Noida, India - 201301') //Set the form field
        PdfContentByte content = stamper.getOverContent(reader.getNumberOfPages())
        Image image = Image.getInstance(new URL("Absolute URL to the image to be embedded"))

        image.setAbsolutePosition(450,650)
        image.scaleAbsolute(200,200)
        content.addImage(image)
        reader.close()
        stamper.close()
        return output.toByteArray() //returns the Byte Array of the PDF contents
    }

And the calling method had code which looked like this :

        File file = new File('/home/vivek/filledForm.pdf') //File to which the filled pdf will be written
        file.bytes = populateFieldsAndSetImage(new File('/home/vivek/form.pdf').bytes) // set the bytes of filledForm.pdf with the byte array returned by populateFieldsAndSetImage()

The PDF had pre filled forms and the identification image also got inserted.

Hope this helps.
Vivek

http://in.linkedin.com/in/svivekkrishna

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Handling Password Protected Pdf with PdfReader

Posted by Hitesh Bhatia on August 19th, 2010

In one of our grails project , we had to attach cover to Pdf file . But since some of pdf’s uploaded were password protected.

To handle this scenario we added bouncyCastle.jar , so our version of iText was able to handle password protected pdf .
And Then to check whether pdf is password protected or not , we used “Boolean isOpenedWithFullPermission()” method.

PdfReader pdf = PdfReader("filePath")
Boolean editable = pdf.isOpenedWithFullPermissions()
 
if(editable){
//attach Cover
}else {
//skip  cover
}

As “isOpenedWithFullPermissions()” returns a Boolean variable ,
it was easy for us to recognize whether we would be able to edit (i.e attach cover in our case) depending on its output. (i,e true or false)
 

_________________________________
Hitesh Bhatia
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Open Pdf in Google Docs using Time Based Cache in Grails

Posted by Hitesh Bhatia on June 23rd, 2010

Recently, we had a requirement where secure URLs were to be made accessible to Google.

Our implementation was to send a url with token valid for 10 seconds. The token expired automatically after 10 seconds. We used time based cache for this as described here: http://snippets.dzone.com/posts/show/2360

T set max time to 10 seconds , I set default MaxAge to 10 millis in above file only which could have also been done easily using its constructor.

Here’s how we did it ,

class AbcController {
    static TimedMap timedMap = new TimedMap()
 
   //  while calling "addDocumentUrl" path of document was passed as params attachmentPath
    def addDocumentUrl = {
 	        String attachmentPath = params.attachmentPath
 	        String token = UUID.randomUUID().toString()
 	        timedMap.put(uniqueIdentification,attachmentPath)
 	        redirect(url: getGoogleUrl(token))          // this will  make google hit specified url
 	    }
 
     String getGoogleUrl(String token) {
 	        String absoluteUrl = ConfigurationHolder.config.builder.absoluteURL
                String GOOGLE_URL="http://docs.google.com/viewer?embedded=true&url="
 	        String googlePath = GOOGLE_URL + absoluteUrl + "/abc/someAction/" + token
 	        return googlePath
 	    }
}

Action someAction was made public so that Google was able to access it. And when Google hits this action it gives token as id.

   def someAction = {
        String key = params.id.toString()
        try {
            String attachmentPath = timedMap.get(key)
            File file = new File(attachmentPath)
            response.setHeader("Content-disposition", "attachment; filename=pdf")
            response.setContentType("application/pdf")
            response.setContentLength(file.size().toInteger());
            OutputStream out = response.getOutputStream();
            out.write(file.readBytes());
            out.flush()
            out.close();
        } catch (Exception e) {
            e.printStackTrace()
        }
    }

_______________________________
Hitesh Bhatia
hitesh@intelligrape.com

http://in.linkedin.com/in/bhatiahitesh

_______________________________

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