HAR Output Format

HAR (HTTP Archive) format is a standard format for storing HTTP request/response data. HAR files can be analyzed with browser DevTools, HAR viewers, or other analysis tools.

Usage

# Output HAR to stdout
logget --har --network https://example.com

# Output HAR to file
logget --har --network --output network.har https://example.com

info

HAR format only includes network data. Use --network with --har.

Output Schemas

When using --har, logget outputs HAR format data following the HTTP Archive specification (version 1.2). The structure is always a single HAR file object, regardless of follow mode.

HAR Structure

{
  "log": {
    "version": "1.2",
    "creator": {
      "name": "logget",
      "version": "2.0"
    },
    "pages": [...],
    "entries": [
      {
        "request": {...},
        "response": {...},
        "timings": {...},
        "cache": {...},
        "time": 123.45,
        "startedDateTime": "2024-10-31T23:00:00.000Z"
      }
    ]
  }
}

Field Descriptions

Root Object

log (object, required): The log object containing all HAR data

Log Object

version (string, required): HAR format version (e.g., "1.2")
creator (object, required): Information about the tool that created the HAR
- name (string): Tool name (e.g., "logget")
- version (string): Tool version (e.g., "2.0")
pages (array, optional): Array of page objects representing pages loaded
entries (array, required): Array of entry objects representing HTTP requests/responses

Page Object

Represents a page load:

{
  "startedDateTime": "2024-10-31T23:00:00.000Z",
  "id": "page_1",
  "title": "Example Domain",
  "pageTimings": {
    "onContentLoad": 123.45,
    "onLoad": 234.56,
    "onDOMContentLoaded": 112.34
  }
}

startedDateTime (string, required): Page load start time (ISO 8601)
id (string, required): Unique page identifier
title (string, required): Page title
pageTimings (object, optional): Page timing information

Entry Object

Represents a single HTTP request/response:

{
  "startedDateTime": "2024-10-31T23:00:00.000Z",
  "time": 123.45,
  "request": {
    "method": "GET",
    "url": "https://example.com/",
    "httpVersion": "HTTP/1.1",
    "headers": [
      {"name": "User-Agent", "value": "Mozilla/5.0..."},
      {"name": "Accept", "value": "text/html"}
    ],
    "queryString": [],
    "cookies": [],
    "headersSize": 234,
    "bodySize": 0
  },
  "response": {
    "status": 200,
    "statusText": "OK",
    "httpVersion": "HTTP/1.1",
    "headers": [
      {"name": "Content-Type", "value": "text/html"},
      {"name": "Content-Length", "value": "1256"}
    ],
    "cookies": [],
    "content": {
      "size": 1256,
      "mimeType": "text/html"
    },
    "redirectURL": "",
    "headersSize": 345,
    "bodySize": 1256
  },
  "cache": {},
  "timings": {
    "blocked": 5.12,
    "dns": 5.34,
    "connect": 10.12,
    "ssl": 20.56,
    "send": 2.10,
    "wait": 30.45,
    "receive": 15.67
  },
  "serverIPAddress": "93.184.216.34",
  "connection": "443"
}

Entry Fields

startedDateTime (string, required): Request start time (ISO 8601)
time (float, required): Total request time in milliseconds
request (object, required): Request object
response (object, required): Response object
cache (object, optional): Cache information
timings (object, required): Timing information
serverIPAddress (string, optional): Server IP address
connection (string, optional): Connection identifier

Request Object

method (string, required): HTTP method (GET, POST, etc.)
url (string, required): Request URL
httpVersion (string, required): HTTP version (e.g., "HTTP/1.1")
headers (array, required): Array of header objects {name, value}
queryString (array, optional): Array of query parameter objects {name, value}
cookies (array, optional): Array of cookie objects
headersSize (integer, optional): Size of request headers in bytes
bodySize (integer, optional): Size of request body in bytes
postData (object, optional): POST data (for POST requests)

Response Object

status (integer, required): HTTP status code
statusText (string, required): HTTP status text (e.g., "OK", "Not Found")
httpVersion (string, required): HTTP version
headers (array, required): Array of header objects {name, value}
cookies (array, optional): Array of cookie objects
content (object, required): Response content
- size (integer): Content size in bytes
- mimeType (string): MIME type
- text (string, optional): Response body text (may be truncated)
redirectURL (string, optional): Redirect URL if applicable
headersSize (integer, optional): Size of response headers in bytes
bodySize (integer, optional): Size of response body in bytes

Timings Object

All timing values are in milliseconds:

blocked (float): Time spent in queue
dns (float): DNS lookup time
connect (float): Connection establishment time
ssl (float): SSL/TLS handshake time (HTTPS only)
send (float): Time to send request
wait (float): Wait time (server processing) - TTFB
receive (float): Time to receive response

info

-1 indicates that the timing information is not available.

Output Format

HAR format always outputs a complete HAR file structure, even in follow mode. The file contains all network entries captured during the session.

Saving to File

# Save to file
logget --har --network --output network.har https://example.com

# Append to file
logget --har --network --append --output network.har https://example.com

Follow Mode

In follow mode (-f), HAR format still outputs a complete HAR file structure. The file is written incrementally as network requests are captured:

logget -f --har --network https://example.com

Examples

Basic Network Capture

logget --har --network https://example.com

Output:

{
  "log": {
    "version": "1.2",
    "creator": {
      "name": "logget",
      "version": "2.0"
    },
    "pages": [
      {
        "startedDateTime": "2024-10-31T23:00:00.000Z",
        "id": "page_1",
        "title": "Example Domain",
        "pageTimings": {
          "onContentLoad": 123.45,
          "onLoad": 234.56
        }
      }
    ],
    "entries": [
      {
        "startedDateTime": "2024-10-31T23:00:00.000Z",
        "time": 123.45,
        "request": {
          "method": "GET",
          "url": "https://example.com/",
          "httpVersion": "HTTP/1.1",
          "headers": [
            {"name": "User-Agent", "value": "Mozilla/5.0..."},
            {"name": "Accept", "value": "text/html,application/xhtml+xml"}
          ],
          "queryString": [],
          "cookies": [],
          "headersSize": 234,
          "bodySize": 0
        },
        "response": {
          "status": 200,
          "statusText": "OK",
          "httpVersion": "HTTP/1.1",
          "headers": [
            {"name": "Content-Type", "value": "text/html; charset=UTF-8"},
            {"name": "Content-Length", "value": "1256"}
          ],
          "cookies": [],
          "content": {
            "size": 1256,
            "mimeType": "text/html"
          },
          "redirectURL": "",
          "headersSize": 345,
          "bodySize": 1256
        },
        "cache": {},
        "timings": {
          "blocked": 5.12,
          "dns": 5.34,
          "connect": 10.12,
          "ssl": 20.56,
          "send": 2.10,
          "wait": 30.45,
          "receive": 15.67
        }
      }
    ]
  }
}

Best Practices

Use with Network Only: Remember to use --network with --har
File Size: HAR files can grow large; consider filtering if needed
Privacy: HAR files may contain sensitive data; be careful when sharing
Analysis Tools: Use browser DevTools or HAR viewers for visual analysis
Automation: Use HAR format for automated analysis workflows

Viewing HAR Files

Browser DevTools

Open Chrome/Edge DevTools (F12)
Go to Network tab
Click the "Import HAR file" button (or right-click → Load HAR)
Select your HAR file

Usage​

Output Schemas​

HAR Structure​

Field Descriptions​

Root Object​

Log Object​

Page Object​

Entry Object​

Entry Fields​

Request Object​

Response Object​

Timings Object​

Output Format​

Saving to File​

Follow Mode​

Examples​

Basic Network Capture​

Best Practices​

Viewing HAR Files​

Browser DevTools​

Online HAR Viewers​