Merge branch 'refactor/const-api-errors' of go/aicra into 0.3.0
allow constants for api.Error and update api.Handler signature - api.EmtyResponse().WithError(api.Error) is the new interface for api.Response - handlers return an api.Response that is wrapped into the final response - server.HandleFunc becomes server.Handle
This commit is contained in:
commit
d3e8d48bc3
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@ -1,70 +1,94 @@
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package api
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var (
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// ErrorSuccess represents a generic successful service execution
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ErrorSuccess = func() Error { return Error{0, "all right", nil} }
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// ErrorFailure is the most generic error
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ErrorFailure = func() Error { return Error{1, "it failed", nil} }
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// ErrorUnknown represents any error which cause is unknown.
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// It might also be used for debug purposes as this error
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// has to be used the less possible
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ErrorUnknown = func() Error { return Error{-1, "", nil} }
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ErrorUnknown Error = -1
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// ErrorSuccess represents a generic successful service execution
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ErrorSuccess Error = 0
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// ErrorFailure is the most generic error
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ErrorFailure Error = 1
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// ErrorNoMatchFound has to be set when trying to fetch data and there is no result
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ErrorNoMatchFound = func() Error { return Error{2, "no resource found", nil} }
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ErrorNoMatchFound Error = 2
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// ErrorAlreadyExists has to be set when trying to insert data, but identifiers or
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// unique fields already exists
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ErrorAlreadyExists = func() Error { return Error{3, "resource already exists", nil} }
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ErrorAlreadyExists Error = 3
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// ErrorConfig has to be set when there is a configuration error
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ErrorConfig = func() Error { return Error{4, "configuration error", nil} }
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ErrorConfig Error = 4
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// ErrorUpload has to be set when a file upload failed
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ErrorUpload = func() Error { return Error{100, "upload failed", nil} }
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ErrorUpload Error = 100
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// ErrorDownload has to be set when a file download failed
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ErrorDownload = func() Error { return Error{101, "download failed", nil} }
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ErrorDownload Error = 101
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// MissingDownloadHeaders has to be set when the implementation
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// of a service of type 'download' (which returns a file instead of
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// a set or output fields) is missing its HEADER field
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MissingDownloadHeaders = func() Error { return Error{102, "download headers are missing", nil} }
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MissingDownloadHeaders Error = 102
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// ErrorMissingDownloadBody has to be set when the implementation
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// of a service of type 'download' (which returns a file instead of
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// a set or output fields) is missing its BODY field
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ErrorMissingDownloadBody = func() Error { return Error{103, "download body is missing", nil} }
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ErrorMissingDownloadBody Error = 103
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// ErrorUnknownService is set when there is no service matching
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// the http request URI.
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ErrorUnknownService = func() Error { return Error{200, "unknown service", nil} }
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ErrorUnknownService Error = 200
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// ErrorUncallableService is set when there the requested service's
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// implementation (plugin file) is not found/callable
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ErrorUncallableService = func() Error { return Error{202, "uncallable service", nil} }
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ErrorUncallableService Error = 202
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// ErrorNotImplemented is set when a handler is not implemented yet
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ErrorNotImplemented Error = 203
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// ErrorPermission is set when there is a permission error by default
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// the api returns a permission error when the current scope (built
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// by middlewares) does not match the scope required in the config.
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// You can add your own permission policy and use this error
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ErrorPermission = func() Error { return Error{300, "permission error", nil} }
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ErrorPermission Error = 300
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// ErrorToken has to be set (usually in authentication middleware) to tell
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// the user that this authentication token is expired or invalid
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ErrorToken = func() Error { return Error{301, "token error", nil} }
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ErrorToken Error = 301
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// ErrorMissingParam is set when a *required* parameter is missing from the
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// http request
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ErrorMissingParam = func() Error { return Error{400, "missing parameter", nil} }
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ErrorMissingParam Error = 400
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// ErrorInvalidParam is set when a given parameter fails its type check as
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// defined in the config file.
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ErrorInvalidParam = func() Error { return Error{401, "invalid parameter", nil} }
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ErrorInvalidParam Error = 401
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// ErrorInvalidDefaultParam is set when an optional parameter's default value
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// does not match its type.
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ErrorInvalidDefaultParam = func() Error { return Error{402, "invalid default param", nil} }
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ErrorInvalidDefaultParam Error = 402
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)
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var errorReasons = map[Error]string{
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ErrorUnknown: "unknown error",
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ErrorSuccess: "all right",
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ErrorFailure: "it failed",
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ErrorNoMatchFound: "resource found",
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ErrorAlreadyExists: "already exists",
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ErrorConfig: "configuration error",
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ErrorUpload: "upload failed",
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ErrorDownload: "download failed",
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MissingDownloadHeaders: "download headers are missing",
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ErrorMissingDownloadBody: "download body is missing",
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ErrorUnknownService: "unknown service",
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ErrorUncallableService: "uncallable service",
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ErrorNotImplemented: "not implemented",
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ErrorPermission: "permission error",
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ErrorToken: "token error",
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ErrorMissingParam: "missing parameter",
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ErrorInvalidParam: "invalid parameter",
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ErrorInvalidDefaultParam: "invalid default param",
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}
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54
api/error.go
54
api/error.go
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@ -1,40 +1,42 @@
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package api
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import (
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"encoding/json"
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"fmt"
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)
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// Error represents an http response error following the api format.
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// These are used by the services to set the *execution status*
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// directly into the response as JSON alongside response output fields.
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type Error struct {
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Code int `json:"code"`
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Reason string `json:"reason"`
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Arguments []interface{} `json:"arguments"`
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}
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type Error int
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// SetArguments set one or multiple arguments to the error
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// to be displayed back to API caller
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func (e *Error) SetArguments(arg0 interface{}, args ...interface{}) {
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// 1. clear arguments */
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e.Arguments = make([]interface{}, 0)
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// 2. add arg[0]
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e.Arguments = append(e.Arguments, arg0)
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// 3. add optional other arguments
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for _, arg := range args {
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e.Arguments = append(e.Arguments, arg)
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}
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}
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// Implements 'error'
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// Error implements the error interface
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func (e Error) Error() string {
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if e.Arguments == nil || len(e.Arguments) < 1 {
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return fmt.Sprintf("[%d] %s", e.Code, e.Reason)
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// use unknown error if no reason
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reason, ok := errorReasons[e]
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if !ok {
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return ErrorUnknown.Error()
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}
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return fmt.Sprintf("[%d] %s (%v)", e.Code, e.Reason, e.Arguments)
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return fmt.Sprintf("[%d] %s", e, reason)
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}
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// MarshalJSON implements encoding/json.Marshaler interface
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func (e Error) MarshalJSON() ([]byte, error) {
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// use unknown error if no reason
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reason, ok := errorReasons[e]
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if !ok {
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return ErrorUnknown.MarshalJSON()
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}
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// format to proper struct
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formatted := struct {
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Code int `json:"code"`
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Reason string `json:"reason"`
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}{
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Code: int(e),
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Reason: reason,
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}
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return json.Marshal(formatted)
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}
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@ -4,28 +4,23 @@ import (
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"strings"
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)
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// HandlerFunc manages an API request
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type HandlerFunc func(Request, *Response)
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// HandlerFn defines the handler signature
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type HandlerFn func(req Request, res *Response) Error
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// Handler is an API handler ready to be bound
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type Handler struct {
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path string
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method string
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handle HandlerFunc
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Fn HandlerFn
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}
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// NewHandler builds a handler from its http method and path
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func NewHandler(method, path string, handlerFunc HandlerFunc) *Handler {
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func NewHandler(method, path string, fn HandlerFn) (*Handler, error) {
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return &Handler{
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path: path,
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method: strings.ToUpper(method),
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handle: handlerFunc,
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}
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}
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// Handle fires a handler
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func (h *Handler) Handle(req Request, res *Response) {
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h.handle(req, res)
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Fn: fn,
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}, nil
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}
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// GetMethod returns the handler's HTTP method
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@ -16,29 +16,20 @@ type Response struct {
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err Error
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}
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// NewResponse creates an empty response. An optional error can be passed as its first argument.
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func NewResponse(errors ...Error) *Response {
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res := &Response{
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// EmptyResponse creates an empty response.
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func EmptyResponse() *Response {
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return &Response{
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Status: http.StatusOK,
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Data: make(ResponseData),
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err: ErrorFailure(),
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err: ErrorFailure,
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Headers: make(http.Header),
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}
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// optional error
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if len(errors) == 1 {
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res.err = errors[0]
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}
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return res
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}
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// SetError sets the error from a base error with error arguments.
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func (res *Response) SetError(baseError Error, arguments ...interface{}) {
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if len(arguments) > 0 {
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baseError.SetArguments(arguments[0], arguments[1:]...)
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}
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res.err = baseError
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// WithError sets the error from a base error with error arguments.
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func (res *Response) WithError(err Error) *Response {
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res.err = err
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return res
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}
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// Error implements the error interface and dispatches to internal error.
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19
http.go
19
http.go
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@ -18,7 +18,7 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
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// 1. find a matching service in the config
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service := server.config.Find(req)
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if service == nil {
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response := api.NewResponse(api.ErrorUnknownService())
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response := api.EmptyResponse().WithError(api.ErrorUnknownService)
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response.ServeHTTP(res, req)
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logError(response)
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return
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@ -30,7 +30,7 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
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// 3. extract URI data
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err := dataset.ExtractURI(req)
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if err != nil {
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response := api.NewResponse(api.ErrorMissingParam())
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response := api.EmptyResponse().WithError(api.ErrorMissingParam)
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response.ServeHTTP(res, req)
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logError(response)
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return
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@ -39,7 +39,7 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
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// 4. extract query data
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err = dataset.ExtractQuery(req)
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if err != nil {
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response := api.NewResponse(api.ErrorMissingParam())
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response := api.EmptyResponse().WithError(api.ErrorMissingParam)
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response.ServeHTTP(res, req)
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logError(response)
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return
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@ -48,7 +48,7 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
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// 5. extract form/json data
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err = dataset.ExtractForm(req)
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if err != nil {
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response := api.NewResponse(api.ErrorMissingParam())
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response := api.EmptyResponse().WithError(api.ErrorMissingParam)
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response.ServeHTTP(res, req)
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logError(response)
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return
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@ -68,15 +68,13 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
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// 7. fail if found no handler
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if foundHandler == nil {
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if found {
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r := api.NewResponse()
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r.SetError(api.ErrorUncallableService(), service.Method, service.Pattern)
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r := api.EmptyResponse().WithError(api.ErrorUncallableService)
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r.ServeHTTP(res, req)
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logError(r)
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return
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}
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r := api.NewResponse()
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r.SetError(api.ErrorUnknownService(), service.Method, service.Pattern)
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r := api.EmptyResponse().WithError(api.ErrorUnknownService)
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r.ServeHTTP(res, req)
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logError(r)
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return
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@ -93,8 +91,9 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
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apireq.Param = dataset.Data
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// 10. execute
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response := api.NewResponse()
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foundHandler.Handle(*apireq, response)
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response := api.EmptyResponse()
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apiErr := foundHandler.Fn(*apireq, response)
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response.WithError(apiErr)
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// 11. apply headers
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res.Header().Set("Content-Type", "application/json; charset=utf-8")
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12
server.go
12
server.go
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@ -47,13 +47,11 @@ func New(configPath string, dtypes ...datatype.T) (*Server, error) {
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}
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// HandleFunc sets a new handler for an HTTP method to a path
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func (s *Server) HandleFunc(httpMethod, path string, handlerFunc api.HandlerFunc) {
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handler := api.NewHandler(httpMethod, path, handlerFunc)
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s.handlers = append(s.handlers, handler)
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}
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// Handle sets a new handler
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func (s *Server) Handle(handler *api.Handler) {
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func (s *Server) Handle(httpMethod, path string, fn api.HandlerFn) {
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handler, err := api.NewHandler(httpMethod, path, fn)
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if err != nil {
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panic(err)
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}
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s.handlers = append(s.handlers, handler)
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}
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