Analyze HTTP traffic in Instruments

Track hierarchy

• HTTP Traffic instruments

  • Number of active tasks

• Process

  • Debuggable process and background tasks daemon

• Session

  • One track per URLSession object

  • Individual task intervals

  • Configurable session name:

let session = URLSession(configuration: .default)
session.sessionDescription = "Main Session"

• Domain

  • Only task that requested in the domain

  • More detail about tasks

  • Individual transactions

  • Transaction states

Task timing

• Structural timing from start till the end

let task = session.dataTask(with: url) {
  /* handle result */ // 👈🏻 Complete event triggers here
}

task.resume() // 👈🏻 Resume event triggers here

Task Identifier

• Ability to read the task identifier for clarity

let task = session.dataTask(with: url) {
  /* handle result */
}
task.taskDescription = "Load Thumbnail"
task.resume()
task.taskIdentifier // 👈🏻 this identifier will be shown in instruments

Task Error

• Ability to distinguish error and success with color

Transactions

• Request + response pair being handled by the URL Loading system

• Contains all the HTTP Layer information

• URL, Http version, connection, cache info

• Request + Response header

• Request + Response body

• And more

Transaction states

• Multiple states to add information for distinction between each block

Instrument

• Focus on the task description

• Expand the task description

• Filter by connection

• Identify the http task issues (Ex: Staircase problem)

• Identify the request (Ex: wrong expiration date of cookie)

• Identify the backtrace (Ex: cached response)

• Filter the session (Ex: Found an issue with the data that sent to server)

• Export the report to .har extension

• Output

• Save and export report to .har to analyse issues

• .har is a JSON structure

Next Steps

• Target app today to detect problems

• Name your URL Session and URLSessionTask for easier debugging

• Adopt latest networking protocols

• Audit your app requests to check if can send less information