daml/navigator/README.md

Navigator

The Navigator is a web-app that connects to any Digital Asset ledger and allows the user to inspect contracts, create contracts, and exercise choices.

The Navigator can be used in development mode (see below) or packaged into a "fat" JAR that includes the compiled frontend assets for distribution.

Navigator architecture

To learn more about developing the different parts of the Navigator see:

• Navigator Frontend README
• Navigator Backend README

Building Navigator

To build a "fat" JAR of the Navigator that includes the pre-compiled front-end assets, run:

bazel build //navigator/backend:navigator-binary_deploy.jar

This produces a "fat" JAR bazel-bin/navigator/backend/navigator-binary_deploy.jar which can be run with:

java -jar bazel-bin/navigator/backend/navigator-binary_deploy.jar

Notable things in the Navigator build:

backend/src/test/resources/schema.graphql

Manually written, must be consistent with backend/src/main/scala/com/digitalasset/navigator/graphql/GraphQLSchema.scala. Consistency is checked in a test.

frontend/src/**/api/Queries.ts

Generated from backend/src/test/resources/schema.graphql with an external codegen tool. Currently, these files are checked in and updated with make update-graphql-types.

frontend bundled code

Code from frontend/src/**/*.ts*, compiled using TypeScript, and bundled with Webpack. Output includes:

• bundle-[hash].js: bundled frontend code, name uses content hasing.
• browsercheck-[hash].js: tiny module for checking browser compatibility, name uses content hasing.
• Several image and font files, referenced by the above modules. File names use content hashing.
• index.html: Single page application main entry, references the above modules.

Note: Browsers are instructed never to cache index.html, and indefinitely cache all other files. This is why content hashing is used.

backend binary

Scala binary, compiled as a fat JAR. Code from backend/src/**/*.scala, bundled frontend code is copied to backend/src/main/resources/frontend.

backend commit and version

The commit and version are included as resource files in the Navigator fat jar. This is to reduce rebuild times when the git commit changes.

frontend development build

For developing frontend code, webpack-dev-server is used. This serves the current frontend code on a separate port, and does:

• Watch *.ts files for changes
• Perform incremental builds
• Send a push notification to the browser, automatically reloading the page when the build is finished.
• Forward network requests to a different port, where a Navigator backend is expected to run.

This is orders of magnitude faster than what the current Bazel build offers, so it is desirable to keep the webpack-dev-server setup working.