Skip to main content

Code Node - Read Text File

This n8n code node reads a file from a previous node and outputs an array of lines from that file. It is particularly useful for processing text files line-by-line in a workflow.

How It Works​

The node first checks for the presence of a binary file in the item.binary.data property, which is the standard way n8n stores file data from nodes like "Read/Write Files from Disk." The code then takes the Base64-encoded string that represents the file's content and converts it back into a binary buffer.

Once the data is in a buffer, the code decodes it into a UTF-8 string, which is the standard character encoding for most text files. Finally, it splits the string into an array of individual lines using the newline character \n as the delimiter.

How to Use​

  • Add a "Read/Write Files from Disk" Node: Start your workflow with this node to read a file from your file system.

  • Add a "Code" Node: Connect the output of the file node to the input of a code node.

  • Paste the Code: Copy and paste the provided code into the code node's editor.

// The 'items' array contains the data from the previous node.
const outputItems = [];

for (const item of items) {
  // Check if there's a binary property named 'data'
  if (item.binary && item.binary.data) {
    // Check if the data is a Base64 string
    const base64Content = item.binary.data.data;
    if (typeof base64Content === 'string') {
      // Decode the Base64 string to a buffer
      const buffer = Buffer.from(base64Content, 'base64');
      
      // Convert the buffer to a string assuming UTF-8 encoding
      const fileContent = buffer.toString('utf8');

      // Split the content by newline characters
      const lines = fileContent.split('\n');
      
      // Create a new item for each line and add it to the output array
      for (const line of lines) {
        outputItems.push({
          json: {
            line: line
          }
        });
      }
    } else {
      // If the data is not a string, handle the original binary case
      outputItems.push({
        json: {
          error: 'Unexpected data format: Expected a Base64 string.'
        }
      });
    }
  } else {
    // If no binary data is found or the structure is unexpected, return an error message
    outputItems.push({
        json: {
          error: 'File content not found in expected binary property structure (item.binary.data).'
        }
      });
  }
}

return outputItems;

or

ReadTextFile.py !!! Uncomment the last line of the python script !!!

  • Execute the Workflow: When the workflow runs, the code node will receive the file's content, process it, and output a JSON object containing an array of lines, accessible via the lines property.

The output will look something like this:

[
    {
    "line": "#!/bin/sh"
    },
    {
    "line": "if [ -d /opt/custom-certificates ]; then"
    },
    {
    "line": "  echo \"Trusting custom certificates from /opt/custom-certificates.\""
    },
    {
      ...
  }
]
Adverts