Doc Engine

Overview

Doc Engine is the system for document search and retrieval. It current handles the following data types

• Document: a database record for a digital file residing on the server.
• BatchRecord: a searchable record in the database that points to the physical location of a batch record

Doc Engine applies strict access control and records all requests for documents in the database.

Client-Server Communication

The search functionality of Doc Engine is exposed via its public API

/api/documents for Document search /api/batchrecords for Batch Record search

Document

Search API

GET /documents

Resource URL: /api/documents

Parameter:

• q(required): JSON string of the search parameters (serial number/title, document level, and labels)
• page_number(optional): if there are more than one page of results (each page has 10 results), this specifies which page the server should return

Response: A JSON string containing the records matching the query, or an empty []

Example Request:

GET /api/documents?query={“sn_title”:”he”,”document_level”:”1”,”labels”:[“2”]}&page_number=1

(Shown as the original strings. In reality, they must be URL-encoded before sending.)

{
"page_number": 1,
"num_pages": 1,
"data":
    [
        {
            "title": "Test 124",
            "labels": [
                {
                    "content": "TEST"
                }
            ],
            "file_url": "/doc_engine/access/4/",
            "version": "1.0",
            "location": "",
            "serial_number": "HE 124"
        },

        {
            "title": "Home, sweet home",
            "labels": [
                {
                    "content": "TEST"
                }
            ],
            "file_url": "/doc_engine/access/10/",
            "version": "1.0",
            "location": "",
            "serial_number": "HE 123121212"
        }
    ]
}

Model

There are two models for storing documents in Doc Engine: Document and FileObject. Document stores the metadata about each document, i.e. the serial number, title, and group permission. It also contains a version number that corresponds to a FileObject, which stores the file path to the actual file on the disk. The user can change the version number for a given Document instance and have it serve a specific version of the file.

Create/Update/Delete

Creating/updating/deleting of records is done via the Django admin interface

Access the actual file and security

The search result provides a link to the actual file at /doc_engine/access/primary key/ . Access control is employed to ensure that only authorized users are permitted to access the document.

Security is ensured through the following mechanisms:

1. Group-based permission model: Each Document has a set of permitted groups. When a user tries to access the document, his/her group membership is checked against that of the Document. Only a user who passes the test will be given access to the file. Others will see “Access Denied.”

2. Access recording: Each time a user attempts to access a document, a record is written in the database, regardless of the outcome (success or access denial).

3. Watermarking of PDF documents: If the document to be accessed is a PDF file, an access watermark is added to the bottom of every page, specifying the user who downloaded the file and the time of access.

Batch Record

API

GET /batchrecords

Resource URL: /api/batchrecords

Parameters:

All the parameters are enclosed in a JSON query string

name optional	Product name for the batch record
batch_number optional	Batch number of the batch record
date_manufactured_from optional date_manufactured_to optional	Specify the date range to search for [date_manufactred_from, date_manufactured_to]

At least one parameter has to be non-empty, otherwise the server returns a 400 error.

Response: A JSON string containing the records matching the query, or an empty []

Example Request:

GET /api/batchrecords?query={“name”:”am”,”batch_number”:”AMP12”,”date_manufactured_from”:”2011-04-01”,”date_manufactured_to”:”2011-09-06”}&page_number=1

(Shown as the original strings. In reality, they must be URL-encoded before sending.)

{
    "page_number": 1,
    "num_pages": 1,
    "data": [
        {
            "date_manufactured": "2011-08-19",
            "batch_number": "AMP12",
            "name": "Ampicillin",
            "date_manufactured_minguo": "0100-08-19",
            "location": "AB 123"
        }
    ]
}

Model

Create/Update/Delete

Creating/updating/deleting of records is done via the Django admin interface.