Simplest step-by-step examples

michurin · michurin · commit dde62937eab2 · 2018-11-10T13:34:51.000+03:00
diff --git a/step-by-step/README.md b/step-by-step/README.md
@@ -0,0 +1,65 @@
+# Simple step-by-step examples
+
+Accompanying materials for my talk on [DevFest Siberia 2018](https://gdg-siberia.com/).
+
+## minimal.go
+
+- Minimal example: one key and on constant response as string "b"
+
+```
+query {a}
+```
+
+## args.go
+
+- Use integer response
+- Two keys
+- Use one integer argument
+- List in response
+
+```
+query {a} # Error: we need nonnull argument
+query {a(x:2)}
+query {a(x:2) b(x:5)}
+query {a b} # Collect all errors
+query {a(x:2) b(x:30)} # Error but collert all reachable data
+```
+
+## type.go
+
+- Simplest custom type with Resolver interface
+- Go structures not must to corelate with GraphQL structs
+- Resolver resolves each field individualy
+- You init part of object in parent resolver
+
+```
+query {a} # You can't call all attrs
+query {a {nm}}
+query {a {nnm}} # Try to suggest fied names
+```
+
+## recursion.go
+
+- Add field by `AddFieldConfig`
+
+```
+query {a {nm sub{nm}}}
+query {a {nm sub{nm sub{nm sub{nm sub{nm}}}}}}
+```
+
+## defer.go
+
+- return `func() (interface{}, error)`
+- use async resolver
+
+```
+query {a {nm}}
+```
+
+## processing.go
+
+- Order of processing
+
+```
+query {a{seq sub{seq sub{seq sub{seq}}}}}
+```
diff --git a/step-by-step/README.run.sh b/step-by-step/README.run.sh
@@ -0,0 +1,41 @@
+#!/bin/bash
+
+while IFS='' read -r line || [[ -n "$line" ]]; do
+  if [[ "$line" =~ '##' ]]
+  then
+    cmd="$(echo $line | sed 's/^##[[:space:]]*//')"
+    echo "[$cmd] Run..."
+    xterm -T "$cmd" -e go run "$cmd" &
+    while :
+    do
+      started="$(netstat -lnt | grep 8080 | wc -l)"
+      if [[ "$started" = '0' ]]
+      then
+        sleep 1
+      else
+        break
+      fi
+    done
+    echo "[$cmd] Call..."
+    while IFS='' read -r line || [[ -n "$line" ]]; do
+      if [[ "$line" = '```' ]]
+      then
+        break
+      fi
+    done
+    while IFS='' read -r line || [[ -n "$line" ]]; do
+      if [[ "$line" = '```' ]]
+      then
+        break
+      fi
+      line="$(echo "$line" | sed 's-#.*--')"
+      echo ">> $line"
+      curl -XPOST http://localhost:8080/gql -H 'Content-Type: application/graphql' -d "$line"
+      echo
+    done
+    echo "[$cmd] Kill..."
+    kill $(jobs -p)
+    echo "[$cmd] Wait..."
+    wait
+  fi
+done < README.md
diff --git a/step-by-step/args.go b/step-by-step/args.go
@@ -0,0 +1,72 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/graphql-go/graphql"
+	"github.com/graphql-go/handler"
+)
+
+func main() {
+	queryType := graphql.NewObject(graphql.ObjectConfig{
+		Name: "Query",
+		Fields: graphql.Fields{
+			"a": &graphql.Field{
+				Name: "a",
+				Type: graphql.Int,
+				Args: graphql.FieldConfigArgument{
+					"x": &graphql.ArgumentConfig{
+						Type: graphql.NewNonNull(graphql.Int),
+					},
+				},
+				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
+					x := p.Args["x"].(int)
+					return x * x, nil
+				},
+			},
+			"b": &graphql.Field{
+				Name: "b",
+				Type: graphql.NewList(graphql.Int),
+				Args: graphql.FieldConfigArgument{
+					"x": &graphql.ArgumentConfig{
+						Type: graphql.NewNonNull(graphql.Int),
+					},
+				},
+				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
+					x := p.Args["x"].(int)
+					if x < 0 || x > 20 {
+						return nil, errors.New("Invald arg")
+					}
+					r := make([]int, x)
+					for i := 0; i < x; i++ {
+						if i < 2 {
+							r[i] = 1
+						} else {
+							r[i] = r[i-1] + r[i-2]
+						}
+					}
+					return r, nil
+				},
+			},
+		},
+	})
+
+	var schema, err = graphql.NewSchema(graphql.SchemaConfig{
+		Query: queryType,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	handler := handler.New(&handler.Config{
+		Schema:     &schema,
+		Pretty:     true,
+		GraphiQL:   true,
+		Playground: true,
+	})
+	http.Handle("/gql", handler)
+	fmt.Println("Run...")
+	http.ListenAndServe(":8080", nil)
+}
diff --git a/step-by-step/defer.go b/step-by-step/defer.go
@@ -0,0 +1,69 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/graphql-go/graphql"
+	"github.com/graphql-go/handler"
+)
+
+type Node struct {
+	Name string
+}
+
+func (n Node) Resolve(p graphql.ResolveParams) (interface{}, error) {
+	switch p.Info.FieldName {
+	case "nm":
+		ch := make(chan string)
+		go func() {
+			ch <- n.Name
+		}()
+		return func() (interface{}, error) {
+			result := <-ch
+			return result, nil
+		}, nil
+	}
+	return nil, errors.New("Node resolver: Unknown field " + p.Info.FieldName)
+}
+
+func main() {
+
+	var nodeType = graphql.NewObject(graphql.ObjectConfig{
+		Name: "Node",
+		Fields: graphql.Fields{
+			"nm": &graphql.Field{Type: graphql.NewNonNull(graphql.String)},
+		},
+	})
+
+	queryType := graphql.NewObject(graphql.ObjectConfig{
+		Name: "Query",
+		Fields: graphql.Fields{
+			"a": &graphql.Field{
+				Name: "a",
+				Type: nodeType,
+				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
+					return Node{"Some constant title"}, nil
+				},
+			},
+		},
+	})
+
+	var schema, err = graphql.NewSchema(graphql.SchemaConfig{
+		Query: queryType,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	handler := handler.New(&handler.Config{
+		Schema:     &schema,
+		Pretty:     true,
+		GraphiQL:   true,
+		Playground: true,
+	})
+	http.Handle("/gql", handler)
+	fmt.Println("Run...")
+	http.ListenAndServe(":8080", nil)
+}
diff --git a/step-by-step/minimal.go b/step-by-step/minimal.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/graphql-go/graphql"
+	"github.com/graphql-go/handler"
+)
+
+func main() {
+	queryType := graphql.NewObject(graphql.ObjectConfig{
+		Name: "Query",
+		Fields: graphql.Fields{
+			"a": &graphql.Field{
+				Name: "a",
+				Type: graphql.String,
+				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
+					return "Value of field 'a'", nil
+				},
+			},
+		},
+	})
+
+	var schema, err = graphql.NewSchema(graphql.SchemaConfig{
+		Query: queryType,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	handler := handler.New(&handler.Config{
+		Schema:     &schema,
+		Pretty:     true,
+		GraphiQL:   true,
+		Playground: true,
+	})
+	http.Handle("/gql", handler)
+	fmt.Println("Run...")
+	http.ListenAndServe(":8080", nil)
+}
diff --git a/step-by-step/processing.go b/step-by-step/processing.go
@@ -0,0 +1,106 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"math/rand"
+	"net/http"
+	"sync/atomic"
+	"time"
+
+	"github.com/graphql-go/graphql"
+	"github.com/graphql-go/handler"
+)
+
+var actionSerial uint64
+
+type Node struct {
+	Name  string
+	Level int
+	Start uint64
+	Ready uint64
+	Fin   uint64
+}
+
+func (n Node) Resolve(p graphql.ResolveParams) (interface{}, error) {
+	switch p.Info.FieldName {
+	case "nm":
+		return n.Name, nil
+	case "lvl":
+		return n.Level, nil
+	case "seq": // h - history
+		return fmt.Sprintf(" %d %d %d ", n.Start, n.Ready, n.Fin), nil
+	case "sub":
+		nextLevel := n.Level + 1
+		nodes := make([]interface{}, 2)
+		for i := 0; i < 2; i++ {
+			atomic.AddUint64(&actionSerial, 1)
+			nn := Node{"Subnode", nextLevel, actionSerial, 0, 0}
+			ch := make(chan Node)
+			go func() {
+				r := rand.Intn(90) + 10
+				time.Sleep(time.Duration(r) * time.Millisecond)
+				atomic.AddUint64(&actionSerial, 1)
+				nn.Ready = actionSerial
+				ch <- nn
+			}()
+			nodes[i] = func() (interface{}, error) {
+				n := <-ch
+				atomic.AddUint64(&actionSerial, 1)
+				n.Fin = actionSerial
+				return n, nil
+			}
+		}
+		return nodes, nil
+	}
+	return nil, errors.New("Node resolver: Unknown field " + p.Info.FieldName)
+}
+
+func main() {
+
+	rand.Seed(time.Now().UTC().UnixNano())
+
+	var nodeType = graphql.NewObject(graphql.ObjectConfig{
+		Name: "Node",
+		Fields: graphql.Fields{
+			"nm":  &graphql.Field{Type: graphql.NewNonNull(graphql.String)},
+			"lvl": &graphql.Field{Type: graphql.NewNonNull(graphql.Int)},
+			"seq": &graphql.Field{Type: graphql.NewNonNull(graphql.String)},
+		},
+	})
+
+	nodeType.AddFieldConfig("sub", &graphql.Field{
+		Type: graphql.NewNonNull(graphql.NewList(graphql.NewNonNull(nodeType))),
+	})
+
+	queryType := graphql.NewObject(graphql.ObjectConfig{
+		Name: "Query",
+		Fields: graphql.Fields{
+			"a": &graphql.Field{
+				Name: "a",
+				Type: nodeType,
+				Resolve: func(p graphql.ResolveParams) (interface{}, error) {
+					actionSerial = 0
+					return Node{"Root node", 0, 0, 0, 0}, nil
+				},
+			},
+		},
+	})
+
+	var schema, err = graphql.NewSchema(graphql.SchemaConfig{
+		Query: queryType,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	handler := handler.New(&handler.Config{
+		Schema:     &schema,
+		Pretty:     true,
+		GraphiQL:   true,
+		Playground: true,
+	})
+	http.Handle("/gql", handler)
+	fmt.Println("Run...")
+	http.ListenAndServe(":8080", nil)
+}
diff --git a/step-by-step/recursion.go b/step-by-step/recursion.go
diff --git a/step-by-step/type.go b/step-by-step/type.go
