An easy way to get From/To list from the postfix.log mainlog. I wanted a quick way to find in the log if postfix received an email.

parsePostfixLog.js

import fs from "fs";
import util from "util";
util.inspect.defaultOptions={depth :null, maxArrayLength: null};

function parseLogSection(section) {
  const lines = section
    .split("\n")
    .map((line) => line.trim())
    .filter((line) => line);
  const result = {
    date: null,
    from: null,
    to: [],
    connect: null,
  };

  for (const line of lines) {
    // Extract date from the first line
    if (!result.date) {
      const dateMatch = line.match(/^\d{8}-(.+?)\s/);
      if (dateMatch) {
        result.date = dateMatch[1].trim();
      }
    }

    // Extract connect
    const connectMatch = line.match(/connect from unknown\[(.+?)\]/);
    if (connectMatch) {
      result.connect = connectMatch[1].trim();
    }

    // Extract from
    const fromMatch = line.match(/from=<([^>]+)>/);
    if (fromMatch) {
      result.from = fromMatch[1].trim();
    }

    // Extract all to fields
    const toMatch = line.match(/to=<([^>]+)>/g);
    if (toMatch) {
      toMatch.forEach((toField) => {
        const email = toField.match(/to=<([^>]+)>/)[1].trim();
        if (!result.to.includes(email)) {
          result.to.push(email);
        }
      });
    }
  }

  return result;
}
function parseToLine(line) {
  const regex = /to=<([^>]+)>/;
  const match = line.match(regex);

  if (match) {
    const to = match[1];
    return to;
  } else {
    return null;
  }
}
function parseFromLine(line) {
  const regex = /from=<([^>]+)>/;
  const match = line.match(regex);

  if (match) {
    const from = match[1];
    return from;
  } else {
    return null;
  }
}
function parseAndConvertDate(logLine) {
  const dateRegex = /^(\w{3} \d{2} \d{2}:\d{2}:\d{2})/;
  const match = logLine.match(dateRegex);

  if (match) {
    const dateString = match[1];
    const currentYear = new Date().getFullYear();
    const date = new Date(`${currentYear} ${dateString} GMT`);

    // Check if the date parsed correctly
    if (!isNaN(date.getTime())) {
      return date.toISOString();
    } else {
      console.error("Invalid date string:", dateString);
      return null;
    }
  } else {
    console.error("No date found in the log line.");
    return null;
  }
}
function parseLogFile(filePath) {
  try {
    const data = fs.readFileSync(filePath, "utf-8");
    const sectionsArray = [];
    let sectionItem = { from: "" };
    const fileLines = data.split("\n");
    for (const line of fileLines) {
      if (line.includes("from=<")) {
        if (sectionItem.to) {
          // console.log(line);
          sectionsArray.push(sectionItem);
          sectionItem = { from: parseFromLine(line) };
          const parsedDate = parseAndConvertDate(line);
          sectionItem = { date: parsedDate, from: parseFromLine(line) };
          continue;
        }
        const parsedDate = parseAndConvertDate(line);
        sectionItem = { date: parsedDate, from: parseFromLine(line) };
      }
      if (line.includes("to=<") && !line.includes("postfix/smtp")) {
        if (!sectionItem.to) {
          sectionItem.to = [];
        }
        sectionItem.to.push(parseToLine(line));
        // console.log(line);
      }
    }

    console.log(sectionsArray);
  } catch (error) {
    console.error(`Error reading file: ${error.message}`);
  }
}

// Example usage
const logFilePath = "postfix.log";
parseLogFile(logFilePath);