Matching Rules of Explicit Want and Implicit Want

Both explicit Want and implicit Want can be used to match an application component to start based on certain rules. These rules determine how the parameters set in want match the configuration file declared by the target application component.

Matching Rules of Explicit Want

The table below describes the matching rules of explicit Want.

Matching Rules for Implicit Want

The table below describes the matching rules of implicit Want.

Get familiar with the following about implicit Want:

• The want parameter passed by the caller indicates the operation to be performed by the caller. It also provides data and application type restrictions.

• The skills field declares the capabilities of the target application component. For details, see the skills tag in the module.json5 file.

The system matches the want parameter (including the action, entities, uri, and type attributes) passed by the caller against the skills configuration (including the actions, entities, uris, and type attributes) of the application components one by one. When all the four attributes are matched, a dialog box is displayed for users to select a matched application.

Matching Rules of action in the want Parameter

The system matches the action attribute in the want parameter passed by the caller against actions under skills of the application components.

• If action in the passed want parameter is unspecified and actions under skills of an application component is unspecified, the matching fails.

• If action in the passed want parameter is specified but actions under skills of an application component is unspecified, the matching fails.

• If action in the passed want parameter is unspecified but actions under skills of an application component is specified, the matching is successful.

• If action in the passed want parameter is specified, and actions under skills of an application component is specified and contains action in the passed want parameter, the matching is successful.

• If action in the passed want parameter is specified, and actions under skills of an application component is specified but does not contain action in the passed want parameter, the matching fails.

Figure 1 Matching rules of action in the want parameter

Matching Rules of entities in the want Parameter

The system matches the entities attribute in the want parameter passed by the caller against entities under skills of the application components.

• If entities in the passed want parameter is unspecified but entities under skills of an application component is specified, the matching is successful.

• If entities in the passed want parameter is unspecified but entities under skills of an application component is unspecified, the matching is successful.

• If entities in the passed want parameter is specified but entities under skills of an application component is unspecified, the matching fails.

• If entities in the passed want parameter is specified, and entities under skills of an application component is specified and contains entities in the passed want parameter, the matching is successful.

• If entities in the passed want parameter is specified, and entities under skills of an application component is specified but does not contain entities in the passed want parameter, the matching fails.

Figure 2 Matching rules of entities in the want parameter

Matching Rules of uri and type in the want Parameter

When the uri and type parameters are specified in the want parameter to initiate an application component startup request, the system traverses the list of installed components and matches the uris array under skills of the application components one by one. If one of the uris arrays under skills matches the uri and type in the passed want, the matching is successful.

There are four combinations of uri and type settings. The matching rules are as follows:

• Neither uri or type is specified in the want parameter.

  • If the uris array under skills of an application component is unspecified, the matching is successful.
  • If the uris array under skills of an application component contains an URI element whose scheme and type are unspecified, the matching is successful.
  • In other cases, the matching fails.

• Only uri is specified in the want parameter.

  • If the uris array under skills of an application component is unspecified, the matching fails.
  • If the uris array under skills of an application component contains an element whose uri is matched and type is unspecified, the matching is successful. Otherwise, the matching fails.
  • If the matching fails for the preceding two scenarios and the input URI is a file path URI, the system obtains the MIME type of the file based on the file name extension. If the MIME type matches type configured under skills, the matching is successful.

• Only type is specified in the want parameter.

  • If the uris array under skills of an application component is unspecified, the matching fails.
  • If the uris array under skills of an application component contains an URI element whose scheme is unspecified and type is matched, the matching is successful. Otherwise, the matching fails.

• Both uri and type are specified in the want parameter, as shown below.

  • If the uris array under skills of an application component is unspecified, the matching fails.
  • If the uris array under skills of an application component contains an element whose uri is matched and type is matched, the matching is successful. Otherwise, the matching fails.

Leftmost URI matching: When only scheme, a combination of scheme and host, or a combination of scheme, host, and port is configured in the uris array under skills of the application component, the matching is successful only if the leftmost URI in the passed want parameter matches scheme, the combination of scheme and host, or the combination of scheme, host, and port.

Figure 3 Matching rules when uri and type are specified in the want parameter

To simplify the description:

• uri in the want parameter passed in by the caller is called w_uri; each element in the uris array under skills of the application component to match is called s_uri.
• type in the want parameter passed in by the caller is called w_type; the type in the uris array under skills of the application component to match is called s_type.

Figure 4 Matching rules of uri and type in the want parameter

Matching Rules of uri

The rules are as follows:

• If scheme of s_uri is unspecified and w_uri is unspecified, the matching is successful. Otherwise, the matching fails.

• If host of s_uri is unspecified and scheme of w_uri and scheme of s_uri are the same, the matching is successful. Otherwise, the matching fails.

• If port of s_uri is unspecified and the combination of scheme and host of w_uri is the same as the combination of scheme and host of s_uri, the matching is successful. Otherwise, the matching fails.

• If path, pathStartWith, and pathRegex of s_uri are unspecified and the combination of scheme, host, and port of w_uri is the same as the combination of scheme, host, and port of s_uri, the matching is successful. Otherwise, the matching fails.

• If path of s_uri is specified and the full path expressions of w_uri and s_uri are the same, the matching is successful. Otherwise, the matching of pathStartWith continues.

• If pathStartWith of s_uri is specified and w_uri contains the prefix expression of s_uri, the matching is successful. Otherwise, pathRegex matching continues.

• If pathRegex of s_uri is specified and w_uri meets the regular expression of s_uri, the matching is successful. Otherwise, the matching fails.

NOTE

The scheme, host, port, path, pathStartWith, and pathRegex attributes of uris under skills of an application component are concatenated. If path, pathStartWith, and pathRegex are declared in sequence, uris can be concatenated into the following expressions:

• Prefix URI expression: When only scheme, a combination of scheme and host, or a combination of scheme, host, and port is configured in the configuration file, the matching is successful if a URI prefixed with the configuration file is passed in.
  • scheme://
  • scheme://host
  • scheme://host:port
• Full path expression: scheme://host:port/path
• Prefix expression: scheme://host:port/pathStartWith
• Regular expression: scheme://host:port/pathRegex

Matching Rules of type

NOTE

The matching rules of type described in this section are based on the fact that type in the want parameter is specified. If type is unspecified, follow the matching rules of uri and type in the want parameter.

The matching rules are as follows:

• If s_type is unspecified, the matching fails.

• If s_type or w_type contains the wildcard */*, the matching is successful.

• If the last character of s_type is the wildcard *, for example, prefixType/*, the matching is successful only when w_type contains prefixType/.

• If the last character of w_type is the wildcard *, for example, prefixType/*, the matching is successful only when s_type contains prefixType/.

你可能感兴趣的鸿蒙文章

harmony 鸿蒙Application Models

harmony 鸿蒙Using Explicit Want to Start an Application Component

harmony 鸿蒙Using Implicit Want to Open a Website

harmony 鸿蒙AbilityStage Component Container

harmony 鸿蒙Accessing a DataAbility

harmony 鸿蒙Accessing a DataShareExtensionAbility from the FA Model

harmony 鸿蒙AccessibilityExtensionAbility

harmony 鸿蒙Common action and entities Values

harmony 鸿蒙API Switching Overview

harmony 鸿蒙Switching of app and deviceConfig