Update DynamoDB table and Lambda functions for Document index

[xinli-cai]

Steps:

1. Update DynamoDB Table with the following attributes:

• Construct a DynamoDB table, key-value pairs should be structured as key=features-properties-id and value= documents a JSON array.
  Here's a sample 'documents' JSON structure:
  "documents": [
  {
  "doc_id": "1" (type:string),
  "type": " " (type: string),
  "url": " " (type: string),
  "text": " " (type: string)
  },
  {
  "doc_id": " 2 " (type:string),
  "type": " " (type: string),
  "url": " " (type: string),
  "text": " " (type: string)
  },
  ....
  {
  "doc_id": " n" (type:string),
  "type": " " (type: string),
  "url": " " (type: string),
  "text": " " (type: string)
  }
  ]

2. Create Lambda functions to extrat infromation from docx, PDF, txt, html format

• Create lambda functions triggerred on a schedule for each document types
• Perform mormalization and processing, including remove space, stopwords, punctuation, and stemming, converting to lower cases, etc from the text
• Store the extracted information as a new column with the DynamoDB table, ensure the text is stored as a json array

[sajjadGG]

updated the table with the following schema
features_properties_id:
documents:{
url:
title:
type:
text:
}
the code is in this branch
https://github.com/Canadian-Geospatial-Platform/document-index/tree/feature/document_index_v2