Class: rpc

LuCI.rpc

The LuCI.rpc class provides high level ubus JSON-RPC abstractions and means for listing and invoking remove RPC methods.

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Methods

addInterceptor(interceptorFn) → {LuCI.rpc~interceptorFn}

Registers a new interceptor function.

Parameters:
Name Type Description
interceptorFn LuCI.rpc~interceptorFn

The inteceptor function to register.
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Returns:

Returns the given function value.

Type
LuCI.rpc~interceptorFn

declare(options) → {LuCI.rpc~invokeFn}

Describes a remote RPC call procedure and returns a function implementing it.

Parameters:
Name Type Description
options LuCI.rpc.DeclareOptions

If any object names are given, this function will return the method signatures of each given object.
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Returns:

Returns a new function implementing the method call described in options.

Type
LuCI.rpc~invokeFn

getBaseURL() → {string}

Returns the current RPC base URL.

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Returns:

Returns the RPC URL endpoint to issue requests against.

Type
string

getSessionID() → {string}

Returns the current RPC session id.

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Returns:

Returns the 32 byte session ID string used for authenticating remote requests.

Type
string

getStatusText(statusCode) → {string}

Translates a numeric ubus error code into a human readable description.

Parameters:
Name Type Description
statusCode number

The numeric status code.
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Returns:

Returns the textual description of the code.

Type
string

list(…objectNamesopt) → {Promise.<(Array.<string>|Object.<string, Object.<string, Object.<string, string>>>)>}

Lists available remote ubus objects or the method signatures of specific objects.

This function has two signatures and is sensitive to the number of arguments passed to it:

  • list() - Returns an array containing the names of all remote ubus objects
  • list("objname", ...) Returns method signatures for each given ubus object name.
Parameters:
Name Type Attributes Description
objectNames string <optional>
<repeatable>

If any object names are given, this function will return the method signatures of each given object.
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Returns:

When invoked without arguments, this function will return a promise resolving to an array of ubus object names. When invoked with one or more arguments, a promise resolving to an object describing the method signatures of each requested ubus object name will be returned.

Type
Promise.<(Array.<string>|Object.<string, Object.<string, Object.<string, string>>>)>

removeInterceptor(interceptorFn) → {boolean}

Removes a registered interceptor function.

Parameters:
Name Type Description
interceptorFn LuCI.rpc~interceptorFn

The inteceptor function to remove.
Source:
Returns:

Returns true if the given function has been removed or false if it has not been found.

Type
boolean

setBaseURL(sid)

Set the RPC base URL to use.

Parameters:
Name Type Description
sid string

Sets the RPC URL endpoint to issue requests against.
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setSessionID(sid)

Set the RPC session id to use.

Parameters:
Name Type Description
sid string

Sets the 32 byte session ID string used for authenticating remote requests.
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Type Definitions

DeclareOptions

Type:
  • Object
Properties:
Name Type Attributes Description
object string

The name of the remote ubus object to invoke.
method string

The name of the remote ubus method to invoke.
params Array.<string> <optional>

Lists the named parameters expected by the remote ubus RPC method. The arguments passed to the resulting generated method call function will be mapped to named parameters in the order they appear in this array.

Extraneous parameters passed to the generated function will not be sent to the remote procedure but are passed to the filter function if one is specified.

Examples:

  • params: [ "foo", "bar" ] - When the resulting call function is invoked with fn(true, false), the corresponding args object sent to the remote procedure will be { foo: true, bar: false }.
  • params: [ "test" ], filter: function(reply, args, extra) { ... } - When the resultung generated function is invoked with fn("foo", "bar", "baz") then { "test": "foo" } will be sent as argument to the remote procedure and the filter function will be invoked with filterFn(reply, [ "foo" ], "bar", "baz")
expect Object.<string, *> <optional>

Describes the expected return data structure. The given object is supposed to contain a single key selecting the value to use from the returned ubus reply object. The value of the sole key within the expect object is used to infer the expected type of the received ubus reply data.

If the received data does not contain expect's key, or if the type of the data differs from the type of the value in the expect object, the expect object's value is returned as default instead.

The key in the expect object may be an empty string ('') in which case the entire reply object is selected instead of one of its subkeys.

If the expect option is omitted, the received reply will be returned as-is, regardless of its format or type.

Examples:

  • expect: { '': { error: 'Invalid response' } } - This requires the entire ubus reply to be a plain JavaScript object. If the reply isn't an object but e.g. an array or a numeric error code instead, it will get replaced with { error: 'Invalid response' } instead.
  • expect: { results: [] } - This requires the received ubus reply to be an object containing a key results with an array as value. If the received reply does not contain such a key, or if reply.results points to a non-array value, the empty array ([]) will be used instead.
  • expect: { success: false } - This requires the received ubus reply to be an object containing a key success with a boolean value. If the reply does not contain success or if reply.success is not a boolean value, false will be returned as default instead.
filter LuCI.rpc~filterFn <optional>

Specfies an optional filter function which is invoked to transform the received reply data before it is returned to the caller.
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filterFn(data, args, …extraArgs) → {*}

The filter function is invoked to transform a received ubus RPC call reply before returning it to the caller.

Parameters:
Name Type Attributes Description
data *

The received ubus reply data or a subset of it as described in the expect option of the RPC call declaration. In case of remote call errors, data is numeric ubus error code instead.
args Array.<*>

The arguments the RPC method has been invoked with.
extraArgs * <repeatable>

All extraneous arguments passed to the RPC method exceeding the number of arguments describes in the RPC call declaration.
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Returns:

The return value of the filter function will be returned to the caller of the RPC method as-is.

Type
*

interceptorFn(msg, req) → {Promise.<*>|*}

Registered interceptor functions are invoked before the standard reply parsing and handling logic.

By returning rejected promises, interceptor functions can cause the invocation function to fail, regardless of the received reply.

Interceptors may also modify their message argument in-place to rewrite received replies before they're processed by the standard response handling code.

A common use case for such functions is to detect failing RPC replies due to expired authentication in order to trigger a new login.

Parameters:
Name Type Description
msg *

The unprocessed, JSON decoded remote RPC method call reply.

Since interceptors run before the standard parsing logic, the reply data is not verified for correctness or filtered according to expect and filter specifications in the declarations.
req Object

The related request object which is an extended variant of the declaration object, allowing access to internals of the invocation function such as filter, expect or params values.
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Returns:

Interceptor functions may return a promise to defer response processing until some delayed work completed. Any values the returned promise resolves to are ignored.

When the returned promise rejects with an error, the invocation function will fail too, forwarding the error to the caller.

Type
Promise.<*> | *

invokeFn(…params) → {Promise.<*>}

The generated invocation function is returned by rpc.declare() and encapsulates a single RPC method call.

Calling this function will execute a remote ubus HTTP call request using the arguments passed to it as arguments and return a promise resolving to the received reply values.

Parameters:
Name Type Attributes Description
params * <repeatable>

The parameters to pass to the remote procedure call. The given positional arguments will be named to named RPC parameters according to the names specified in the params array of the method declaration.

Any additional parameters exceeding the amount of arguments in the params declaration are passed as private extra arguments to the declared filter function.
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Returns:

Returns a promise resolving to the result data of the remote ubus RPC method invocation, optionally substituted and filtered according to the expect and filter declarations.

Type
Promise.<*>