https://github.com/emaringolo/seaside-server-timing

HTTP Server-Timing support for Seaside
https://github.com/emaringolo/seaside-server-timing

performance-analysis seaside smalltalk web-development

Last synced: 4 days ago
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HTTP Server-Timing support for Seaside

• Host: GitHub
• URL: https://github.com/emaringolo/seaside-server-timing
• Owner: eMaringolo
• Created: 2020-07-10T03:46:23.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2021-06-28T01:52:52.000Z (over 3 years ago)
• Last Synced: 2024-10-31T06:41:46.137Z (about 2 months ago)
• Topics: performance-analysis, seaside, smalltalk, web-development
• Language: Smalltalk
• Homepage:
• Size: 65.4 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Introduction

Implements a request filter that automatically collects performance notifications

during a request and adds them to the `Server-Timing` heading in the response, this enables the web development tools to show server timing information to

better analyze the timing of a request/response cycle.

![Server Timing Screenshot](img/server-timing-screenshot.png)

# How to use

Add a `WAPerformanceTimingFilter` to your request handler as follows:

```smalltalk

myApp := (WADispatcher default handlerAt: 'myApp')

            addFilter: WAPerformanceTimingFilter new

```

Then in your code you signal performance notifications as follows:

```smalltalk

(WAPerformanceTiming name: 'callback' description: 'Callback procesing' duration: 80 milliseconds) signal

```

You can also do:

```smalltalk

WAPerformanceTiming measure: 'metricName' during: aBlock

```

# Installation

```smalltalk

Metacello new

	baseline: 'SeasidePerformanceTiming';

	repository: 'github://eMaringolo/seaside-server-timing/src';

	onConflictUseLoaded; "Just in case you have an older version of Seaside Installed"

	load.

```

# Remarks

## Header combination

Seaside's `WAHeaderFields` object corectly supports adding multiple values for the same header name via `aWAHeaderFields at: key add: value` or via `aWAResponse headerAt: key append: value`.

But the `ZnZincServerAdaptor>>responseFrom: aRequestContext` iteration over such headers only adds the last one. For this reason the filter manually updates the header value each time, breaking somehow the the encapsulation of `WAHeaderFields`. Once this is solved at the `ZnZincServerAdaptor` side, this behavior should be removed from the `WAPerformanceTimingFilter`.

## Counter behavior

Each timing notification gets immediately added to the request header, so there is no _"counter"_ functionality of each indicator. It is, if you signal a `WAPerformanceTiming` with the same name twice, this will be added twice as well to the headers. So it doesn't work as a performance counter of any sort.

# References

* [Server-Timing Working Draft](https://www.w3.org/TR/server-timing/)

* [Server-Timing MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Server-Timing)