A component URL is a URL that identifies a component.
This section describes the syntax used for displaying URLs to users.
A component URL can, in principle, have any scheme. Some common schemes you may encounter are:
A fuchsia-pkg component URL is a package URL that locates a component distributed in a Fuchsia package.
It has the same format as package URL, with a resource path relative to the package root that locates a component manifest. This path is usually of the form meta/<manifest_name>.cm.
fuchsia-pkg://<repo-hostname>[/<pkg-name>[/<pkg-variant>][?hash=<pkg-hash>][#<path-to-manifest>]]
Example:
fuchsia-pkg://fuchsia.com/stash#meta/stash_secure.cm
A fuchsia-boot component URL locates a component in the system boot image. This scheme is used to identify components that must be resolved during early boot before a fuchsia-pkg resolver is available. It has the following format:
fuchsia-boot:///<path-to-manifest-in-bootfs>
Example:
fuchsia-boot:///#meta/driver_manager.cm
An http(s) component URL identifies a web page as a component. Such a component could be executed as a web page in a web runner, for example.
Example:
https://en.wikipedia.org/wiki/Hippos
The Component Framework supports a subset of relative URLs (Relative URLs are defined in URL RFC 3986). Specifically, Component Framework supports relative path URLs (plus a URL fragment with the path to the component manifest) to subpackaged components, and fragment-only URLs.
The path to the component manifest is the only content allowed in a relative component URL fragment (#meta/<component>.cm). If the fragment contains any other content, or if a relative component includes URL query parameters (?key=value), the component will not resolve.
A relative path URL is resolved at runtime based on a known “context”. For components resolving a child component by relative URL, the context is a resolver-supplied value associated with the parent component. The URL path is interpreted as the name of one of the declared subpackages of the parent component's package.
Relative subpackage path URLs start with a relative package URL and have the following format:
<subpackage-path>#<path-to-manifest>
Example:
child#meta/default.cm
For more information on subpackages and subpackaged components, see the documentation on Fuchsia Subpackages.
A relative fragment-only URL is resolved at runtime based on the URL of the parent component's package. Fragment-only URLs have the following format:
#<path-to-manifest>
Example:
#meta/child.cm
For a fuchsia-pkg parent component with the following URL:
fuchsia-pkg://fuchsia.com/package#meta/component.cm
The relative URL resolves to:
fuchsia-pkg://fuchsia.com/package#meta/child.cm
