渲染PDF文件并使用grails渲染和Attachmentable插件保存到对象

Question

I am attempting to generate a PDF file that contains object information and then attach it to another object that is stored in the database. The attachmentable plugin I am using is working now for user end attachments, but I need my system to be able to do it automatically.

I am using:
Grails 1.3.9
Attachmentable 0.3.0 http://grails.org/plugin/attachmentable
Rendering 0.4.3 http://grails.org/plugin/rendering

I have been able to generate and display the pdf, but do not know how to attach it using the attachmentable plugin. I need some way to take the generated pdf byte array and convert it to a MultipartFile for the attachmentable plugin function I call. The error I get shows that my argument types are invalid.

I save object1 and object2, then generate the pdf of object1 and try to attach it to object2.

Thanks in advance for you help!

Thing1 Controller Snippets:

ByteArrayOutputStream bytes = pdfRenderingService.render(template: "/thing1/pdf", model: [thing1: thing1])

attachmentableService.addAttachment("unknown", thing2.id, bytes)

AttachmentableService function I am attempting to call:

def addAttachment(def poster, def reference, CommonsMultipartFile file) {
    addAttachment(CH.config, poster, reference, file)
}

def addAttachment(def config,
                  def poster,
                  def reference,
                  CommonsMultipartFile file) {

    if (reference.ident() == null) {
        throw new AttachmentableException(
            "You must save the entity [${delegate}] before calling addAttachment.")
    }

    if (!file?.size) {
        throw new EmptyFileException(file.name, file.originalFilename)
    }

    String delegateClassName = AttachmentableUtil.fixClassName(reference.class)
    String posterClass = (poster instanceof String) ? poster : AttachmentableUtil.fixClassName(poster.class.name)
    Long posterId = (poster instanceof String) ? 0L : poster.id
    String filename = file.originalFilename

    // link
    def link = AttachmentLink.findByReferenceClassAndReferenceId(
            delegateClassName, reference.ident())
    if (!link) {
        link = new AttachmentLink(
                referenceClass: delegateClassName,
                referenceId: reference.ident())
    }

    // attachment
    Attachment attachment = new Attachment(
            // file
            name: FilenameUtils.getBaseName(filename),
            ext: FilenameUtils.getExtension(filename),
            length: 0L,
            contentType: file.contentType,
            // poster
            posterClass: posterClass,
            posterId: posterId,
            // input
            inputName: file.name)
    link.addToAttachments attachment

    if (!link.save(flush: true)) {
        throw new AttachmentableException(
                "Cannot create Attachment for arguments [$user, $file], they are invalid.")
    }

    // save file to disk
    File diskFile = AttachmentableUtil.getFile(config, attachment, true)
    file.transferTo(diskFile)

    attachment.length = diskFile.length()

    // interceptors
    if(reference.respondsTo('onAddAttachment')) {
        reference.onAddAttachment(attachment)
    }

    attachment.save(flush:true) // Force update so searchable can try to index it again.

    return reference
}

Grails runtime error:

groovy.lang.MissingMethodException: No signature of method: com.macrobit.grails.plugins.attachmentable.services.AttachmentableService.addAttachment() is applicable for argument types: (java.lang.String, java.lang.Long, java.io.ByteArrayOutputStream) values: [unknown, 80536, %PDF-1.4 and a long string of unreadable data...]
Possible solutions: addAttachment(java.lang.Object, java.lang.Object, org.springframework.web.multipart.commons.CommonsMultipartFile), addAttachment(java.lang.Object, java.lang.Object, java.lang.Object, org.springframework.web.multipart.commons.CommonsMultipartFile)

Service Method I Added:

def customAddMethod(def poster, def reference, def pdfBytes) {
    customAddMethod(CH.config, poster, reference, pdfBytes)
}

def customAddMethod(def config,
                  def poster,
                  def reference,
                  def pdfBytes) {

    if (reference.ident() == null) {
        throw new AttachmentableException(
            "You must save the entity [${delegate}] before calling customAddMethod.")
    }

    String delegateClassName = AttachmentableUtil.fixClassName(reference.class)
    String posterClass = (poster instanceof String) ? poster : AttachmentableUtil.fixClassName(poster.class.name)
    Long posterId = (poster instanceof String) ? 0L : poster.id
    String filename = "File Name"

    // link
    def link = AttachmentLink.findByReferenceClassAndReferenceId(
            delegateClassName, reference.ident())

    if (!link) {
        link = new AttachmentLink(
                referenceClass: delegateClassName,
                referenceId: reference.ident())
    }

    // attachment
    Attachment attachment = new Attachment(
            // file
            name: "File Name",
            ext: "pdf",
            length: 0L,
            contentType: "application/pdf",
            // poster
            posterClass: posterClass,
            posterId: posterId,
            // input
            inputName: "File Name")
    link.addToAttachments attachment

    if (!link.save(flush: true)) {
        throw new AttachmentableException(
                "Cannot create Attachment for arguments [$user, $file], they are invalid.")
    }

    // save file to disk
    byte[] bytes = pdfBytes.toByteArray(); //convert ByteArrayOutputStream to ByteArray

    File diskFile = AttachmentableUtil.getFile(config, attachment, true) //file path
    FileOutputStream fos = new FileOutputStream(diskFile); //open file output stream to write to
    fos.write(bytes); //write rendered pdf bytes to file
    fos.flush();
    fos.close();

    attachment.length = diskFile.length()

    // interceptors
    if(reference.respondsTo('onAddAttachment')) {
        reference.onAddAttachment(attachment)
    }

    attachment.save(flush:true) // Force update so searchable can try to index it again.

    return reference
}

Answer 1

It looks like the AttachmentableService you referenced (from the Attachmentable plugin) assumes it's dealing with a file-upload scenario, such that you could easily grab the MultipartFile instance via request.getFile(). That's not the case for you - you're creating the file via the Rendering plugin, and you want that file attached to a domain object, right?

You could try constructing a CommonsMultipartFile instance manually by first writing the pdf bytes to disk, and then create a DiskFileItem via DiskFileItemFactory. See this post for an example of what I'm thinking: How to make CommonsMultipartFile from absolute file path?

Another, better, option might be to checkout that plugin's source and add a method that doesn't require you to go through those gyrations - perhaps a version of the addAttachment method that accepts a File or an OutputStream instead - and submit a PR to the plugin author. (Looks like they're adding an 'addAttachment' method to qualifying domain objects, which also expects a CommonsMultipartFile).

Otherwise, you might just have to create your own service to basically provide the same end result, which apparently is to create an AttachmentLink and associated Attachment instance.