Parsing natural language to structure output

In the previous section, we hardcoded Malaysia into the Mediastack Node’s input. But what if we want users to specify their own news filters dynamically using natural language?

Goal

We will modify our workflow so that:

The user inputs a query like “latest news in Japan today”.
ChatGPT extracts structured details from the input (e.g., country, category, keyword).
The extracted details are passed to the Mediastack Node, dynamically filtering news.

Step 1: Add a New ChatGPT Node for Information Extraction

We need a new ChatGPT node to extract structured data from the user’s input before passing it to the Mediastack Node.

Let's remove the connection of input and output node, instead connect it to another ChatOpenAI Node

Connect the Input Node’s message output to the new ChatGPT Node’s message input.

Test it by sending the message:

“latest news in Malaysia today”
Right now, ChatGPT doesn’t understand what to do, because we haven’t given it proper instructions.

Step 2: Instruct ChatGPT to Extract Information

To make ChatGPT extract information, we need to provide a system instruction. However, the ChatGPT Node only has one input, but we need to send both a system instruction and user query. In this case, we use JavaScript Node combines them into a single string, ensuring ChatGPT processes the request properly.

Add a JavaScript Node

Double-click an empty space in the editor and search for JavaScript to quickly add it.
Name it "System Prompt" for clarity.
Define two inputs:
- User Input (user - string) → This will hold the user’s message.
- System Prompt (system - string) → This will contain the instruction: "Extract the country, category, and keyword from the following user request"
Define one output (output - string).

Modify the JavaScript Code

Inside the Function Code of the JavaScript Node, enter the following:
```
return `system: ${inputs[1]}\n user: ${inputs[0]}`;
```

This ensures that ChatGPT receives the prompt in a structured format:

system: Extract the country, category, and keyword from the following user request
user: latest news in Malaysia today

Link the Inputs & Outputs

Connect:
- The user’s message from the Input Node to the User Input of the JavaScript Node.
- A Text Area Node containing the system instruction to the System Input of the JavaScript Node.
- The JavaScript Node's output to the message input of the ChatGPT Node.

Test the Setup

Type: "latest news in Malaysia today"
ChatGPT should now able to extract the information

Step 3: Using a JSON Schema for ChatGPT Extraction

In the previous step, we saw that the extracted data was incorrect

country: Malaysia
category: news
keyword: latest news today

This happens because ChatGPT doesn’t know exactly how to format its response based on the Mediastack API requirements.

To fix this, we will provide a JSON Schema to standardize the extracted data format.

Prepare the JSON Schema

We generated the JSON Schema for the Mediastack Live News API using ChatGPT and the official JSON Schema standards (json-schema.org).

Here is an example JSON Schema that enforces the correct format:

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "sources": {
      "type": "string",
      "description": "Use this parameter to include or exclude one or multiple comma-separated news sources. Example: 'cnn,-bbc' to include CNN and exclude BBC.",
      "pattern": "^[a-zA-Z0-9,-]+$"
    },
    "categories": {
      "type": "string",
      "description": "Use this parameter to include or exclude one or multiple comma-separated news categories. Example: 'business,-sports' to include business and exclude sports.",
      "pattern": "^[a-zA-Z,-]+$"
    },
    "countries": {
      "type": "string",
      "description": "Use this parameter to include or exclude one or multiple comma-separated countries. Example: 'au,-us' to include Australia and exclude the US.",
      "pattern": "^[a-zA-Z,-]+$"
    },
    "languages": {
      "type": "string",
      "description": "Use this parameter to include or exclude one or multiple comma-separated languages. Example: 'en,-de' to include English and exclude German.",
      "pattern": "^[a-zA-Z,-]+$"
    },
    "keywords": {
      "type": "string",
      "description": "Use this parameter to search for sentences or exclude words. Example: 'new movies 2021 -matrix' to search for 'New movies 2021' but exclude 'Matrix'."
    },
    "date": {
      "type": "string",
      "description": "Use this parameter to specify a date or date range. Examples: '2020-01-01' for a specific date or '2020-12-24,2020-12-31' for a date range.",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}(,\\d{4}-\\d{2}-\\d{2})?$"
    },
    "sort": {
      "type": "string",
      "description": "Use this parameter to specify a sorting order. Available values: 'published_desc' (default), 'published_asc', 'popularity'.",
      "enum": [
        "published_desc",
        "published_asc",
        "popularity"
      ],
      "default": "published_desc"
    },
    "limit": {
      "type": "integer",
      "description": "Use this parameter to specify a pagination limit (number of results per page). Default is 25, maximum allowed is 100.",
      "minimum": 1,
      "maximum": 100,
      "default": 25
    },
    "offset": {
      "type": "integer",
      "description": "Use this parameter to specify a pagination offset value. Default is 0, starting with the first available result.",
      "minimum": 0,
      "default": 0
    }
  },
  "additionalProperties": false
}

Integrate the JSON Schema into ChatGPT

Add a "Const Data" Node to store the JSON Schema.
- Double-click an empty space in the editor, search Data, and add it.
- Paste the JSON Schema into the Const Data Node.
Modify the System Prompt
- Change the prompt in the Text Area Node to:
  Extract the mediastack data from the following user request
Connect the Schema to the ChatGPT Node
- Link the Const Data (JSON Schema Node) to the Schema input of the ChatGPT Node.
- Now, ChatGPT will refer to the schema before generating the extracted response.

Test the result

Send a message like:
```
latest sports news in Japan today
```

The correct output should now be:

{
    "categories": "sports",
    "countries": "jp",
    "date": "2023-12-07"
}

Step 4: Connect everything together

Next, we’ll connect the structured data to the Mediastack API and dynamically fetch news based on user input!

Since ChatGPT outputs JSON as a string instead of an actual JSON object. We need to parse the stringified JSON before passing it to Mediastack

Create a JavaScript Node to Parse JSON

Since ChatGPT outputs JSON as a string instead of an actual JSON object. We need to parse the stringified JSON before passing it to Mediastack

Double-click an empty space in the editor and search for JavaScript.
Rename it to "Parse JSON" for clarity.
Set Code, Inputs and Outputs accordingly.

Link the Nodes

Connect ChatGPT's response output → Parse JSON Node’s input.
Parse JSON Node’s output → Mediastack News Node’s countries, category, and keywords inputs.
Use an Object Property Node (if needed) to extract specific fields from the parsed JSON.

Test the Workflow

Send: "latest sports news in Malaysia today"
Mediastack should now correctly receive the extracted country, category, and keyword and replied with relevent information

Summary

So now we have successfully create a agent that reply with news based on user's prompt.

Here is the exported JSON file containing the full workflow setup. You can import this into Editor to instantly recreate the agent.

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Last updated 4 months ago