insomnia/DEVELOPMENT.md

Development Overview

The purpose of this document is to provide a general overview of the application architecture.

Technologies

Insomnia is a desktop application built on top of Electron. Electron provides a Chromium runtime for the Insomnia web app to run inside of, as well as additional tools to provide access to operating system features.

There are a few more technologies and tools worth mentioning:

• React is the library used for all UI components.
• Less is used for styling UI components.
• Electron Builder is used to help build, sign, and package Insomnia for distribution.
• Flow is used for adding types to the codebase. Not everything is Flow but all new code should be typed with Flow.
• Webpack is the bundler used to compile the JS/Less/babel/etc libcurl library that Insomnia uses to make requests. Libcurl is the HTTP client of choice because it allows the deepest amount of debuggability and control of HTTP requests.
• nedb a local in-memory database.
• node-libcurl is a NodeJS wrapper around the native.
• Codemirror is a web-based, extendable, code editor used for highlighting and linting of data formats like JSON, GraphQL, and XML.

Project Structure

Insomnia uses lerna to manage multiple npm packages within a single repository. There are currently two package locations:

• /packages contains related packages that are consumed by insomnia-app or externally.
• /plugins contains plugin packages that are included by default with the application.

The insomnia-app Main Package

/packages/insomnia-app is the entry point for the app. All other packages are imported from this one.

There are a few notable directories inside of it:

• /main.development.js Entry for Electron.
• /app/main Stuff that runs inside Electron's main process.
• /app/ui React components and styling .
• /app/common Utilities used across both main and render processes.
• /app/plugins Logic around installation and usage of plugins.
• /app/models DB models used to store user data.
• /app/network Sending requests and performing auth (eg. OAuth 2).
• /app/templating Nunjucks and rendering related code.
• /app/sync(-legacy)? and /app/accounts Team sync and account stuff.

Data and State Architecture

Insomnia stores data in a few places:

• A local in-memory NeDB database stores data for data models (requests, folder, workspaces, etc).
• A local Redux store contains an in-memory copy of all database entities.

Eventually, Redux could/should be removed, which would both reduce memory overhead and simplify the codebase. NeDB should essentially replace it

Technical Debt

This is just brief summary of Insomnia's current technical debt.

• Loading large responses (~20MB) can crash the app on weaker hardware.
• Redux stores an in-memory duplicate of the local DB, unnecessarily doubling memory usage. Moving forward, Redux shouldn't need to be considered much and may be able to be removed eventually.
• Bundling libcurl (native module) has caused many weeks of headaches trying to get builds working across Windows, Mac, and Linux. More expertise here is definitely needed.
• All input fields that support templating/autocomplete/etc are actually Codemirror instances. This isn't really debt but may affect things going forward.
• Use of libcurl means Insomnia can't run in a web browser and can't support bidirectional socket communication.