How to measure how many TCP connections were made on a page

Question

Using the chrome dev tool, I can see the number of requests per page, but it seems that there is no way to measure the number of connections.

Is this possible in the chrome dev tool? if not, what tools can i use instead?

Answer 1

You can include the connection identifier header in the Network panel, which is a unique identifier for a specific connection. You can sort the column to see how many queries were for a particular connection instance, but there is no built-in way to see how many or filter the results.

However, this data can be exported to a formatted JSON file known as HAR (HTTP Archive). You can do this by right-clicking on the panel and selecting Save As HAR With Content.

You can extract data from JSON, as well as filter and group as you like. I created a simple example script that will download the HAR from the local file system, analyze the data and filter the content so that it shows how many unique connection identifiers appeared in the session.

function loadFile(event) { var file = event.target.files[0]; if (file) { var reader = new FileReader(); reader.onload = function(e) { var contents = e.target.result; var data = JSON.parse(contents); getUniqueConnectionCount(data); } reader.readAsText(file); } else { alert('Failed to load file.'); } } function getUniqueConnectionCount(data) { var entries = data.log.entries; var uniqueConnectionIds = entries.map(function(item) { return item['connection']; }).filter(function(x, i, a) { return a.indexOf(x) === i && i > 0; }); console.log('There were ', uniqueConnectionIds.length, ' unique connections found', uniqueConnectionIds); } document.getElementById('files').addEventListener('change', loadFile, false); 

 <div> <input type='file' id='files' name='files' /> </div> 

Note. Make sure the "Save Log" is not checked to avoid viewing data from previous sessions. This is just a quick example for your use case, but I might consider expanding it.