# Block merger

This microservice is used to extract text from a digital document in a structured format (paragraph, image, table), which is then used for translation purposes.

## Architecture

* It takes an image or pdf as an input.
* If the input is a pdf, it converts the pdf into images.
* The `pdftohtml` tool is used to extract page-level information like text, word coordinates, page width, page height, tables, images, and others.
* If the document language is vernacular, the `pdftohtml` tool does not work well, so we use Tesseract (or GV if required Alternatively) for OCR.
* Horizontal merging is used to get lines using word coordinates.
* Vertical merging is used to get blocks using line coordinates.
* The final JSON contains page-level information like page width, page height, paragraphs, lines, words, and layout class.
* **API Contract:** [here](/modules/block-merger.md)
* **Code location:** [here](/modules/block-merger.md)

## Modules

### API Details

#### Local Testing

**URL:** <http://0.0.0.0:5001/anuvaad-etl/block-merger/v0/merge-blocks>

**Input:**

```json
{
    "input": {
        "files": [
            {
                "locale": "en",
                "path": "1.pdf",
                "type": "pdf"
            }
        ]
    },
    "jobID": "BM-15913540488115873",
    "state": "INITIATED",
    "status": "STARTED",
    "stepOrder": 0,
    "workflowCode": "abc",
    "tool": "BM",
    "metadata": { 
        "module": "WORKFLOW-MANAGER",
        "receivedAt": 15993163946431696,
        "sessionID": "4M1qOZj53tIZsCoLNzP0oP",
        "userID": "d4e0b570-b72a-44e5-9110-5fdd54370a9d"
    }
}
```

Here it takes a PDF or image path as an input and the language of that document.

#### Workflow Initiate

**URL:** <https://auth.anuvaad.org/anuvaad-etl/wf-manager/v1/workflow/async/initiate>

**Input:**

```json
{
    "workflowCode": "WF_A_BM",
    "files": [
        {
            "path": "763b0d80-4e82-423f-a432-23ddffe5ad92.pdf",
            "type": "pdf",
            "locale": "en"
        }
    ]
}
```

#### Steps:

1. **Upload a PDF or image file using the upload API:**

   **Upload URL:** <https://auth.anuvaad.org/anuvaad-api/file-uploader/v0/upload-file>
2. **Get the upload ID and copy that to the path of wf-initiate input of the block merger.**
3. **Do bulk search using jobIDs to get JSON ID of the BM service response:**

   **Bulk search URL:** <https://auth.anuvaad.org/anuvaad-etl/wf-manager/v1/workflow/jobs/search/bulk>

   **Bulk search input format:**

   ```json
   {
       "jobIDs": ["A_B-MtrjS-1640069221694"],
       "taskDetails": true
   }
   ```
4. **Download JSON using download API:**

   **Download URL:** <https://auth.anuvaad.org/download/0-1640069280533983.json>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://anuvaad.sunbird.org/modules/block-merger.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.