Documentation ¶
Overview ¶
Package jsonrpc provides a JSON-RPC 2.0 client that sends JSON-RPC requests and receives JSON-RPC responses using HTTP.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Params ¶
func Params(params ...interface{}) interface{}
Params is a helper function that uses the same parameter syntax as Call(). But you should consider to always use NewRequest() instead.
e.g. to manually create an RPCRequest object:
request := &RPCRequest{ Method: "myMethod", Params: Params("Alex", 35, true), }
same with new request: request := NewRequest("myMethod", "Alex", 35, true)
If you know what you are doing you can omit the Params() call but potentially create incorrect rpc requests:
request := &RPCRequest{ Method: "myMethod", Params: 2, <-- invalid since a single primitive value must be wrapped in an array --> no magic without Params() }
correct:
request := &RPCRequest{ Method: "myMethod", Params: []int{2}, <-- invalid since a single primitive value must be wrapped in an array }
Types ¶
type HTTPClient ¶ added in v1.5.0
HTTPClient is an abstraction for a HTTP client
type HTTPError ¶
type HTTPError struct { Code int // contains filtered or unexported fields }
HTTPError represents a error that occurred on HTTP level.
An error of type HTTPError is returned when a HTTP error occurred (status code) and the body could not be parsed to a valid RPCResponse object that holds a RPCError.
Otherwise a RPCResponse object is returned with a RPCError field that is not nil.
func NewHTTPError ¶ added in v1.0.1
type RPCClient ¶
type RPCClient interface { // Call is used to send a JSON-RPC request to the server endpoint. // // The spec states, that params can only be an array or an object, no primitive values. // So there are a few simple rules to notice: // // 1. no params: params field is omitted. e.g. Call("getinfo") // // 2. single params primitive value: value is wrapped in array. e.g. Call("getByID", 1423) // // 3. single params value array or object: value is unchanged. e.g. Call("storePerson", &Person{Name: "Alex"}) // // 4. multiple params values: always wrapped in array. e.g. Call("setDetails", "Alex, 35, "Germany", true) // // Examples: // Call("getinfo") -> {"method": "getinfo"} // Call("getPersonId", 123) -> {"method": "getPersonId", "params": [123]} // Call("setName", "Alex") -> {"method": "setName", "params": ["Alex"]} // Call("setMale", true) -> {"method": "setMale", "params": [true]} // Call("setNumbers", []int{1, 2, 3}) -> {"method": "setNumbers", "params": [1, 2, 3]} // Call("setNumbers", 1, 2, 3) -> {"method": "setNumbers", "params": [1, 2, 3]} // Call("savePerson", &Person{Name: "Alex", Age: 35}) -> {"method": "savePerson", "params": {"name": "Alex", "age": 35}} // Call("setPersonDetails", "Alex", 35, "Germany") -> {"method": "setPersonDetails", "params": ["Alex", 35, "Germany"}} // // for more information, see the examples or the unit tests Call(ctx context.Context, method string, params ...interface{}) (*RPCResponse, error) // CallRaw is like Call() but without magic in the requests.Params field. // The RPCRequest object is sent exactly as you provide it. // See docs: NewRequest, RPCRequest, Params() // // It is recommended to first consider Call() and CallFor() CallRaw(ctx context.Context, request *RPCRequest) (*RPCResponse, error) // CallFor is a very handy function to send a JSON-RPC request to the server endpoint // and directly specify an object to store the response. // // out: will store the unmarshaled object, if request was successful. // should always be provided by references. can be nil even on success. // the behaviour is the same as expected from json.Unmarshal() // // method and params: see Call() function // // if the request was not successful (network, http error) or the rpc response returns an error, // an error is returned. if it was an JSON-RPC error it can be casted // to *RPCError. // CallFor(ctx context.Context, out interface{}, method string, params ...interface{}) error // CallBatch invokes a list of RPCRequests in a single batch request. // // Most convenient is to use the following form: // CallBatch(RPCRequests{ // Batch("myMethod1", 1, 2, 3), // Batch("myMethod2), "Test"), // }) // // You can create the []*RPCRequest array yourself, but it is not recommended and you should notice the following: // - field Params is sent as provided, so Params: 2 forms an invalid json (correct would be Params: []int{2}) // - you can use the helper function Params(1, 2, 3) to use the same format as in Call() // - field JSONRPC is overwritten and set to value: "2.0" // - field ID is overwritten and set incrementally and maps to the array position (e.g. requests[5].ID == 5) // // // Returns RPCResponses that is of type []*RPCResponse // - note that a list of RPCResponses can be received unordered so it can happen that: responses[i] != responses[i].ID // - RPCPersponses is enriched with helper functions e.g.: responses.HasError() returns true if one of the responses holds an RPCError CallBatch(ctx context.Context, requests RPCRequests) (RPCResponses, error) // CallBatchRaw invokes a list of RPCRequests in a single batch request. // It sends the RPCRequests parameter is it passed (no magic, no id autoincrement). // // Consider to use CallBatch() instead except you have some good reason not to. // // CallBatchRaw(RPCRequests{ // &RPCRequest{ // ID: 123, // this won't be replaced in CallBatchRaw // JSONRPC: "wrong", // this won't be replaced in CallBatchRaw // Method: "myMethod1", // Params: []int{1}, // there is no magic, be sure to only use array or object // }, // &RPCRequest{ // ID: 612, // JSONRPC: "2.0", // Method: "myMethod2", // Params: Params("Alex", 35, true), // you can use helper function Params() (see doc) // }, // }) // // Returns RPCResponses that is of type []*RPCResponse // - note that a list of RPCResponses can be received unordered // - the id's must be mapped against the id's you provided // - RPCPersponses is enriched with helper functions e.g.: responses.HasError() returns true if one of the responses holds an RPCError CallBatchRaw(ctx context.Context, requests RPCRequests) (RPCResponses, error) CallForInto(ctx context.Context, out interface{}, method string, params []interface{}) error CallWithCallback(ctx context.Context, method string, params []interface{}, callback func(*http.Request, *http.Response) error) error Close() error }
RPCClient sends JSON-RPC requests over HTTP to the provided JSON-RPC backend.
RPCClient is created using the factory function NewClient().
func NewClient ¶
NewClient returns a new RPCClient instance with default configuration.
endpoint: JSON-RPC service URL to which JSON-RPC requests are sent.
func NewClientWithOpts ¶
func NewClientWithOpts(endpoint string, opts *RPCClientOpts) RPCClient
NewClientWithOpts returns a new RPCClient instance with custom configuration.
endpoint: JSON-RPC service URL to which JSON-RPC requests are sent.
opts: RPCClientOpts provide custom configuration
type RPCClientOpts ¶
type RPCClientOpts struct { HTTPClient HTTPClient CustomHeaders map[string]string }
RPCClientOpts can be provided to NewClientWithOpts() to change configuration of RPCClient.
HTTPClient: provide a custom http.Client (e.g. to set a proxy, or tls options)
CustomHeaders: provide custom headers, e.g. to set BasicAuth
type RPCError ¶
type RPCError struct { Code int `json:"code"` Message string `json:"message"` Data interface{} `json:"data,omitempty"` }
RPCError represents a JSON-RPC error object if an RPC error occurred.
Code: holds the error code
Message: holds a short error message
Data: holds additional error data, may be nil
type RPCRequest ¶
type RPCRequest struct { Method string `json:"method"` Params interface{} `json:"params,omitempty"` ID int `json:"id"` JSONRPC string `json:"jsonrpc"` }
RPCRequest represents a JSON-RPC request object.
Method: string containing the method to be invoked
Params: can be nil. if not must be an json array or object
ID: may always set to 1 for single requests. Should be unique for every request in one batch request.
JSONRPC: must always be set to "2.0" for JSON-RPC version 2.0
See: http://www.jsonrpc.org/specification#request_object
Most of the time you shouldn't create the RPCRequest object yourself. The following functions do that for you: Call(), CallFor(), NewRequest()
If you want to create it yourself (e.g. in batch or CallRaw()), consider using Params(). Params() is a helper function that uses the same parameter syntax as Call().
e.g. to manually create an RPCRequest object:
request := &RPCRequest{ Method: "myMethod", Params: Params("Alex", 35, true), }
If you know what you are doing you can omit the Params() call to avoid some reflection but potentially create incorrect rpc requests:
request := &RPCRequest{ Method: "myMethod", Params: 2, <-- invalid since a single primitive value must be wrapped in an array --> no magic without Params() }
correct:
request := &RPCRequest{ Method: "myMethod", Params: []int{2}, <-- invalid since a single primitive value must be wrapped in an array }
func NewRequest ¶
func NewRequest(method string, params ...interface{}) *RPCRequest
NewRequest returns a new RPCRequest that can be created using the same convenient parameter syntax as Call()
e.g. NewRequest("myMethod", "Alex", 35, true)
type RPCRequests ¶
type RPCRequests []*RPCRequest
RPCRequests is of type []*RPCRequest. This type is used to provide helper functions on the request list
type RPCResponse ¶
type RPCResponse struct { JSONRPC string `json:"jsonrpc"` Result stdjson.RawMessage `json:"result,omitempty"` Error *RPCError `json:"error,omitempty"` ID int `json:"id"` }
RPCResponse represents a JSON-RPC response object.
Result: holds the result of the rpc call if no error occurred, nil otherwise. can be nil even on success.
Error: holds an RPCError object if an error occurred. must be nil on success.
ID: may always be 0 for single requests. is unique for each request in a batch call (see CallBatch())
JSONRPC: must always be set to "2.0" for JSON-RPC version 2.0
See: http://www.jsonrpc.org/specification#response_object
func (*RPCResponse) GetObject ¶
func (RPCResponse *RPCResponse) GetObject(toType interface{}) error
GetObject converts the rpc response to an arbitrary type.
The function works as you would expect it from json.Unmarshal()
type RPCResponses ¶
type RPCResponses []*RPCResponse
RPCResponses is of type []*RPCResponse. This type is used to provide helper functions on the result list
func (RPCResponses) AsMap ¶
func (res RPCResponses) AsMap() map[int]*RPCResponse
AsMap returns the responses as map with response id as key.
func (RPCResponses) GetByID ¶
func (res RPCResponses) GetByID(id int) *RPCResponse
GetByID returns the response object of the given id, nil if it does not exist.
func (RPCResponses) HasError ¶
func (res RPCResponses) HasError() bool
HasError returns true if one of the response objects has Error field != nil