182 lines
4.8 KiB
Go
182 lines
4.8 KiB
Go
package lambdarouter
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import (
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"encoding/json"
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"net/http"
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"strings"
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radix "github.com/armon/go-radix"
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"github.com/aws/aws-lambda-go/events"
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)
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const (
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post = http.MethodPost
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get = http.MethodGet
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put = http.MethodPut
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patch = http.MethodPatch
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delete = http.MethodDelete
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)
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// APIGRequest is used as the input of handler functions.
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// The Claims, Path, and QryStr will be populated by the the APIGatewayProxyRequest.
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// The Request itself is also passed through if you need further access.
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type APIGRequest struct {
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Claims map[string]interface{}
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Path map[string]string
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QryStr map[string]string
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Request *events.APIGatewayProxyRequest
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}
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// APIGResponse is used as the output of handler functions.
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// Populate Status and Body with your http response or populate Err with your error.
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type APIGResponse struct {
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Status int
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Body []byte
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Err error
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}
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// APIGHandler is the interface a handler function must implement to be used
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// with Get, Post, Put, Patch, and Delete.
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type APIGHandler func(req *APIGRequest, res *APIGResponse)
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// APIGRouter is the object that handlers build upon and is used in the end to respond.
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type APIGRouter struct {
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request *events.APIGatewayProxyRequest
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endpoints map[string]*radix.Tree
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params map[string]string
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svcprefix string
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}
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// NOTE: Begin router methods.
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// NewAPIGRouter creates a new router using the request and a prefix to strip from your incoming requests.
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func NewAPIGRouter(r *events.APIGatewayProxyRequest, svcprefix string) *APIGRouter {
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return &APIGRouter{
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request: r,
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endpoints: map[string]*radix.Tree{
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post: radix.New(),
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get: radix.New(),
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put: radix.New(),
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patch: radix.New(),
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delete: radix.New(),
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},
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params: map[string]string{},
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svcprefix: svcprefix,
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}
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}
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// Get creates a new get endpoint.
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func (r *APIGRouter) Get(route string, handlers ...APIGHandler) {
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r.addEndpoint(get, route, handlers)
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}
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// Post creates a new post endpoint.
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func (r *APIGRouter) Post(route string, handlers ...APIGHandler) {
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r.addEndpoint(post, route, handlers)
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}
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// Put creates a new put endpoint.
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func (r *APIGRouter) Put(route string, handlers ...APIGHandler) {
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r.addEndpoint(put, route, handlers)
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}
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// Patch creates a new patch endpoint
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func (r *APIGRouter) Patch(route string, handlers ...APIGHandler) {
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r.addEndpoint(patch, route, handlers)
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}
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// Delete creates a new delete endpoint.
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func (r *APIGRouter) Delete(route string, handlers ...APIGHandler) {
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r.addEndpoint(delete, route, handlers)
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}
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// Respond returns an APIGatewayProxyResponse to respond to the lambda request.
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func (r *APIGRouter) Respond() events.APIGatewayProxyResponse {
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var (
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handlersInterface interface{}
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ok bool
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status int
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respbody []byte
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err error
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endpointTree = r.endpoints[r.request.HTTPMethod]
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path = strings.TrimPrefix(r.request.Path, "/"+r.svcprefix)
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response = events.APIGatewayProxyResponse{}
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)
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for k := range r.params {
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p := strings.TrimPrefix(k, "{")
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p = strings.TrimSuffix(p, "}")
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if r.request.PathParameters[p] != "" {
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path = strings.Replace(path, r.request.PathParameters[p], k, -1)
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}
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}
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if handlersInterface, ok = endpointTree.Get(path); !ok {
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respbody, _ := json.Marshal(map[string]string{"error": "no route matching path found"})
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response.StatusCode = http.StatusNotFound
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response.Body = string(respbody)
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return response
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}
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handlers := handlersInterface.([]APIGHandler)
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for _, handler := range handlers {
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req := &APIGRequest{
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Path: r.request.PathParameters,
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QryStr: r.request.QueryStringParameters,
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Request: r.request,
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}
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if r.request.RequestContext.Authorizer["claims"] != nil {
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req.Claims = r.request.RequestContext.Authorizer["claims"].(map[string]interface{})
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}
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res := &APIGResponse{}
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handler(req, res)
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status, respbody, err = res.deconstruct()
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if err != nil {
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respbody, _ := json.Marshal(map[string]string{"error": err.Error()})
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if strings.Contains(err.Error(), "record not found") {
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status = 204
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} else if status < 400 {
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status = 400
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}
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response.StatusCode = status
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response.Body = string(respbody)
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return response
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}
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}
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response.StatusCode = status
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response.Body = string(respbody)
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return response
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}
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// NOTE: Begin helper functions.
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func stripSlashesAndSplit(s string) []string {
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s = strings.TrimPrefix(s, "/")
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s = strings.TrimSuffix(s, "/")
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return strings.Split(s, "/")
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}
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func (res *APIGResponse) deconstruct() (int, []byte, error) {
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return res.Status, res.Body, res.Err
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}
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func (r *APIGRouter) addEndpoint(method string, route string, handlers []APIGHandler) {
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if _, overwrite := r.endpoints[method].Insert(route, handlers); overwrite {
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panic("endpoint already existent")
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}
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rtearr := stripSlashesAndSplit(route)
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for _, v := range rtearr {
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if strings.HasPrefix(v, "{") {
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r.params[v] = "" // adding params as keys with {brackets}
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}
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}
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}
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