1 files changed, 283 insertions, 0 deletions
diff --git a/vendor/github.com/99designs/gqlgen/handler/graphql.go b/vendor/github.com/99designs/gqlgen/handler/graphql.go
new file mode 100644
index 00000000..9d222826
--- /dev/null
+++ b/vendor/github.com/99designs/gqlgen/handler/graphql.go
@@ -0,0 +1,283 @@
+package handler
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/99designs/gqlgen/complexity"
+	"github.com/99designs/gqlgen/graphql"
+	"github.com/gorilla/websocket"
+	"github.com/hashicorp/golang-lru"
+	"github.com/vektah/gqlparser"
+	"github.com/vektah/gqlparser/ast"
+	"github.com/vektah/gqlparser/gqlerror"
+	"github.com/vektah/gqlparser/validator"
+)
+
+type params struct {
+	Query         string                 `json:"query"`
+	OperationName string                 `json:"operationName"`
+	Variables     map[string]interface{} `json:"variables"`
+}
+
+type Config struct {
+	cacheSize       int
+	upgrader        websocket.Upgrader
+	recover         graphql.RecoverFunc
+	errorPresenter  graphql.ErrorPresenterFunc
+	resolverHook    graphql.FieldMiddleware
+	requestHook     graphql.RequestMiddleware
+	complexityLimit int
+}
+
+func (c *Config) newRequestContext(doc *ast.QueryDocument, query string, variables map[string]interface{}) *graphql.RequestContext {
+	reqCtx := graphql.NewRequestContext(doc, query, variables)
+	if hook := c.recover; hook != nil {
+		reqCtx.Recover = hook
+	}
+
+	if hook := c.errorPresenter; hook != nil {
+		reqCtx.ErrorPresenter = hook
+	}
+
+	if hook := c.resolverHook; hook != nil {
+		reqCtx.ResolverMiddleware = hook
+	}
+
+	if hook := c.requestHook; hook != nil {
+		reqCtx.RequestMiddleware = hook
+	}
+
+	return reqCtx
+}
+
+type Option func(cfg *Config)
+
+func WebsocketUpgrader(upgrader websocket.Upgrader) Option {
+	return func(cfg *Config) {
+		cfg.upgrader = upgrader
+	}
+}
+
+func RecoverFunc(recover graphql.RecoverFunc) Option {
+	return func(cfg *Config) {
+		cfg.recover = recover
+	}
+}
+
+// ErrorPresenter transforms errors found while resolving into errors that will be returned to the user. It provides
+// a good place to add any extra fields, like error.type, that might be desired by your frontend. Check the default
+// implementation in graphql.DefaultErrorPresenter for an example.
+func ErrorPresenter(f graphql.ErrorPresenterFunc) Option {
+	return func(cfg *Config) {
+		cfg.errorPresenter = f
+	}
+}
+
+// ComplexityLimit sets a maximum query complexity that is allowed to be executed.
+// If a query is submitted that exceeds the limit, a 422 status code will be returned.
+func ComplexityLimit(limit int) Option {
+	return func(cfg *Config) {
+		cfg.complexityLimit = limit
+	}
+}
+
+// ResolverMiddleware allows you to define a function that will be called around every resolver,
+// useful for tracing and logging.
+func ResolverMiddleware(middleware graphql.FieldMiddleware) Option {
+	return func(cfg *Config) {
+		if cfg.resolverHook == nil {
+			cfg.resolverHook = middleware
+			return
+		}
+
+		lastResolve := cfg.resolverHook
+		cfg.resolverHook = func(ctx context.Context, next graphql.Resolver) (res interface{}, err error) {
+			return lastResolve(ctx, func(ctx context.Context) (res interface{}, err error) {
+				return middleware(ctx, next)
+			})
+		}
+	}
+}
+
+// RequestMiddleware allows you to define a function that will be called around the root request,
+// after the query has been parsed. This is useful for logging and tracing
+func RequestMiddleware(middleware graphql.RequestMiddleware) Option {
+	return func(cfg *Config) {
+		if cfg.requestHook == nil {
+			cfg.requestHook = middleware
+			return
+		}
+
+		lastResolve := cfg.requestHook
+		cfg.requestHook = func(ctx context.Context, next func(ctx context.Context) []byte) []byte {
+			return lastResolve(ctx, func(ctx context.Context) []byte {
+				return middleware(ctx, next)
+			})
+		}
+	}
+}
+
+// CacheSize sets the maximum size of the query cache.
+// If size is less than or equal to 0, the cache is disabled.
+func CacheSize(size int) Option {
+	return func(cfg *Config) {
+		cfg.cacheSize = size
+	}
+}
+
+const DefaultCacheSize = 1000
+
+func GraphQL(exec graphql.ExecutableSchema, options ...Option) http.HandlerFunc {
+	cfg := Config{
+		cacheSize: DefaultCacheSize,
+		upgrader: websocket.Upgrader{
+			ReadBufferSize:  1024,
+			WriteBufferSize: 1024,
+		},
+	}
+
+	for _, option := range options {
+		option(&cfg)
+	}
+
+	var cache *lru.Cache
+	if cfg.cacheSize > 0 {
+		var err error
+		cache, err = lru.New(DefaultCacheSize)
+		if err != nil {
+			// An error is only returned for non-positive cache size
+			// and we already checked for that.
+			panic("unexpected error creating cache: " + err.Error())
+		}
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodOptions {
+			w.Header().Set("Allow", "OPTIONS, GET, POST")
+			w.WriteHeader(http.StatusOK)
+			return
+		}
+
+		if strings.Contains(r.Header.Get("Upgrade"), "websocket") {
+			connectWs(exec, w, r, &cfg)
+			return
+		}
+
+		var reqParams params
+		switch r.Method {
+		case http.MethodGet:
+			reqParams.Query = r.URL.Query().Get("query")
+			reqParams.OperationName = r.URL.Query().Get("operationName")
+
+			if variables := r.URL.Query().Get("variables"); variables != "" {
+				if err := jsonDecode(strings.NewReader(variables), &reqParams.Variables); err != nil {
+					sendErrorf(w, http.StatusBadRequest, "variables could not be decoded")
+					return
+				}
+			}
+		case http.MethodPost:
+			if err := jsonDecode(r.Body, &reqParams); err != nil {
+				sendErrorf(w, http.StatusBadRequest, "json body could not be decoded: "+err.Error())
+				return
+			}
+		default:
+			w.WriteHeader(http.StatusMethodNotAllowed)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+
+		var doc *ast.QueryDocument
+		if cache != nil {
+			val, ok := cache.Get(reqParams.Query)
+			if ok {
+				doc = val.(*ast.QueryDocument)
+			}
+		}
+		if doc == nil {
+			var qErr gqlerror.List
+			doc, qErr = gqlparser.LoadQuery(exec.Schema(), reqParams.Query)
+			if len(qErr) > 0 {
+				sendError(w, http.StatusUnprocessableEntity, qErr...)
+				return
+			}
+			if cache != nil {
+				cache.Add(reqParams.Query, doc)
+			}
+		}
+
+		op := doc.Operations.ForName(reqParams.OperationName)
+		if op == nil {
+			sendErrorf(w, http.StatusUnprocessableEntity, "operation %s not found", reqParams.OperationName)
+			return
+		}
+
+		if op.Operation != ast.Query && r.Method == http.MethodGet {
+			sendErrorf(w, http.StatusUnprocessableEntity, "GET requests only allow query operations")
+			return
+		}
+
+		vars, err := validator.VariableValues(exec.Schema(), op, reqParams.Variables)
+		if err != nil {
+			sendError(w, http.StatusUnprocessableEntity, err)
+			return
+		}
+		reqCtx := cfg.newRequestContext(doc, reqParams.Query, vars)
+		ctx := graphql.WithRequestContext(r.Context(), reqCtx)
+
+		defer func() {
+			if err := recover(); err != nil {
+				userErr := reqCtx.Recover(ctx, err)
+				sendErrorf(w, http.StatusUnprocessableEntity, userErr.Error())
+			}
+		}()
+
+		if cfg.complexityLimit > 0 {
+			queryComplexity := complexity.Calculate(exec, op, vars)
+			if queryComplexity > cfg.complexityLimit {
+				sendErrorf(w, http.StatusUnprocessableEntity, "query has complexity %d, which exceeds the limit of %d", queryComplexity, cfg.complexityLimit)
+				return
+			}
+		}
+
+		switch op.Operation {
+		case ast.Query:
+			b, err := json.Marshal(exec.Query(ctx, op))
+			if err != nil {
+				panic(err)
+			}
+			w.Write(b)
+		case ast.Mutation:
+			b, err := json.Marshal(exec.Mutation(ctx, op))
+			if err != nil {
+				panic(err)
+			}
+			w.Write(b)
+		default:
+			sendErrorf(w, http.StatusBadRequest, "unsupported operation type")
+		}
+	})
+}
+
+func jsonDecode(r io.Reader, val interface{}) error {
+	dec := json.NewDecoder(r)
+	dec.UseNumber()
+	return dec.Decode(val)
+}
+
+func sendError(w http.ResponseWriter, code int, errors ...*gqlerror.Error) {
+	w.WriteHeader(code)
+	b, err := json.Marshal(&graphql.Response{Errors: errors})
+	if err != nil {
+		panic(err)
+	}
+	w.Write(b)
+}
+
+func sendErrorf(w http.ResponseWriter, code int, format string, args ...interface{}) {
+	sendError(w, code, &gqlerror.Error{Message: fmt.Sprintf(format, args...)})
+}