Downloading content from URL without prompting for authentication in Grails - grails

Question

I am working on a web app programmed in Grails. I have a page used to display a certain report and these reports can contain attachments. The attachment is stored in documentum and currently, when the user clicks on it, it is only a link to the location in documentum where the attachment is stored and prompts the user for his credentials. My app has documentum credentials stored in the configuration file therefore I want to use those rather than forcing the user to enter his own credentials. I am using RESTful services to retrieve link but I am trying to find a way to use the link to download directly to the users computer.
private def getFileInfo(def id, def subject) {
// product show view needs the following four lists to display the document information correctly
def ATRReportInstance = ATRReport.findByTrackingNumber(id)
def linkList = []
def nameList = []
def formatList = []
def idList = []
// open up a connection to the documentum server
def doc = connectToDocumentum()
if (!doc) return
def rest = doc.rest
def response = doc.response
if (response.status == 200) {
// retrieve the folder for this product (the name of this folder is the product's ID)
def rObjectId = rest.get(documentumServer + "/repositories/" + documentumfilestore + "?dql=select r_object_id from dm_folder where any r_folder_path='" + atrreportfolderpath + "/" + id + "'") {
auth authuser, authpass
}
// get the folder's ID from the folder object retrieved above
def folderObjectID
rObjectId.json.entries.each {
entry - >
folderObjectID = entry.content.properties.r_object_id
}
// get all of the documents in the product's MSDS folder using the folder ID retrieved above
def resp = rest.get(documentumServer + "/repositories/" + documentumfilestore + "?dql=select r_object_id, object_name, a_content_type, subject from cbs_document where any i_folder_id= '" + folderObjectID + "'") {
auth authuser, authpass
}
// cycle through the documents above to populate the four MSDS document information lists
def x = 0
resp.json.entries.each {
entry - >
if (entry.content.properties.subject == subject) {
// get the document's content object from the document's ID
def content = rest.get(documentumServer + "/repositories/" + documentumfilestore + "/objects/" + entry.content.properties.r_object_id + "/contents/content" + "?media-url-policy=local") {
auth authuser, authpass
}
if (entry.content.properties.r_object_id != null && ATRReportInstance.inactiveFiles != null && ATRReportInstance.inactiveFiles.contains(entry.content.properties.r_object_id.toString())) {} else {
linkList[x] = getLink(content.json.links, "enclosure")
if (linkList[x].contains("format=msg"))
linkList[x] = linkList[x].toString().substring(0, linkList[x].toString().indexOf("content-media")) + "content-media.msg"
formatList[x] = entry.content.properties.a_content_type
nameList[x] = entry.content.properties.object_name
idList[x] = entry.content.properties.r_object_id
x++
}
}
}
return [linkList: linkList, nameList: nameList, formatList: formatList, idList: idList]
} else {
// return null if documentum is unavailable
flash.message = message(code: 'error.documentum.unavailable')
return null
}
}
I'm thinking writing another function that can take in a URL and download the document to the user might work, but I can't figure how to retrieve that document within Grails.

Answer 1

If you want to bypass login you could either setup a SSO solution (requires some work for DCTM) or do a function as you suggest. However you should consider the licensing terms when doing this.

Answer 2

Here is the solution I implemented and that worked. It is a method that downloads a file in documentum using authentication credentials found in a configuration file.
def exportAttachment() {
//uses parameters from gsp file
def url = params.url
def name = params.name
def format = params.format
def extension
//find proper extension
for (s in documentumExtMap) {
if (s.value.equals(format)) {
extension = s.key
}
}
def connection = new URL(url).openConnection()
def remoteAuth = "Basic " + "${authuser}:${authpass}".bytes.encodeBase64()
connection.setRequestProperty("Authorization", remoteAuth)
def dataStream = connection.inputStream
response.setContentType("application/octet-stream")
response.setHeader('Content-disposition', 'Attachment; filename=' + name + '.' + extension)
response.outputStream << dataStream
response.outputStream.flush()
}
The method has three parameters: url, name, format.
Url is the location of the file in documentum.
Name is the name of the download client side
Format is the type of file that is being downloaded. In my case, I had to use this to get the proper extension needed for the file.