feat: client generation

codegen/codegen.go

@@ -36,6 +36,7 @@ import (
 // Most callers to this package will use Generate.
 type Options struct {
 	GenerateServer bool              // GenerateChiServer specifies whether to generate chi server boilerplate
+	GenerateClient bool              // GenerateClient specifies whether to generate client boilerplate
 	GenerateTypes  bool              // GenerateTypes specifies whether to generate type definitions
 	EmbedSpec      bool              // Whether to embed the swagger spec in the generated code
 	SkipFmt        bool              // Whether to skip go imports on the generated code
@@ -207,6 +208,18 @@ func Generate(swagger *openapi3.T, packageName string, opts Options) (string, er
 		}
 	}
 
+	if opts.GenerateClient {
+		clientOut, err := GenerateClient(t, ops)
+		if err != nil {
+			return "", fmt.Errorf("error writing client: %w", err)
+		}
+
+		_, err = w.WriteString(clientOut)
+		if err != nil {
+			return "", fmt.Errorf("error writing client: %w", err)
+		}
+	}
+
 	if opts.EmbedSpec {
 		_, err = w.WriteString(inlinedSpec)
 		if err != nil {
@@ -610,6 +623,19 @@ func GenerateAdditionalPropertyBoilerplate(t *template.Template, typeDefs []Type
 	return GenerateTemplates([]string{"additional-properties.tmpl"}, t, context)
 }
 
+func GenerateClient(
+	t *template.Template,
+	ops []OperationDefinition,
+) (string, error) {
+	context := struct {
+		Operations []OperationDefinition
+	}{
+		Operations: ops,
+	}
+
+	return GenerateTemplates([]string{"client.tmpl"}, t, context)
+}
+
 // SanitizeCode runs sanitizers across the generated Go code to ensure the
 // generated code will be able to compile.
 func SanitizeCode(goCode string) string {

codegen/codegen_test.go

@@ -2,10 +2,15 @@ package codegen
 
 import (
 	"go/format"
+	"go/token"
+	"go/types"
+	"net/url"
+	"os"
 	"testing"
 	"text/template"
 
 	examplePetstore "github.com/discord-gophers/goapi-gen/examples/petstore-expanded/api"
+	"golang.org/x/tools/go/packages"
 
 	"github.com/discord-gophers/goapi-gen/templates"
 	"github.com/getkin/kin-openapi/openapi3"
@@ -439,3 +444,88 @@ func (t *MyType) FromValue(value int64) error {
 		})
 	}
 }
+
+func TestGenerateClientFormat(t *testing.T) {
+	// Input vars for code generation:
+	opts := Options{
+		GenerateClient: true,
+		GenerateTypes:  true,
+	}
+
+	// Get a spec from the example PetStore definition:
+	swagger, err := examplePetstore.GetSwagger()
+	assert.NoError(t, err)
+
+	// Run our code generation:
+	code, err := Generate(swagger, "petstore", opts)
+	assert.NoError(t, err)
+
+	tfs := token.NewFileSet()
+	tfs.AddFile("petstore.gen.go", tfs.Base(), len(code))
+	cwd, _ := os.Getwd()
+	pkgs, err := packages.Load(&packages.Config{
+		Mode: packages.NeedSyntax | packages.NeedTypes | packages.NeedImports,
+		Fset: tfs,
+		Overlay: map[string][]byte{
+			cwd + "/petstore/petstore.gen.go": []byte(code),
+		},
+	}, "./petstore")
+	assert.NoError(t, err)
+	assert.Len(t, pkgs, 1)
+	pkg := pkgs[0]
+	assert.Empty(t, pkg.Errors)
+
+	// check we import the requests package
+	_, ok := pkg.Imports["github.com/carlmjohnson/requests"]
+	assert.True(t, ok)
+
+	client := pkg.Types.Scope().Lookup("Client")
+	assert.NotNil(t, client)
+
+	assert.True(t, client.Exported())
+	assert.Equal(t, 4, client.Type().Underlying().(*types.Struct).NumFields())
+}
+
+func TestGenerateK8sClient(t *testing.T) {
+	uri, err := url.Parse("https://raw.githubusercontent.com/kubernetes/kubernetes/master/api/openapi-spec/v3/api__v1_openapi.json")
+	assert.NoError(t, err)
+	swagger, err := openapi3.NewLoader().LoadFromURI(uri)
+	assert.NoError(t, err)
+
+	// Run our code generation:
+	code, err := Generate(swagger, "k8s", Options{
+		GenerateClient: true,
+		GenerateTypes:  true,
+	})
+	if of := os.Getenv("OUT_FILE"); of != "" {
+		assert.NoError(t, os.WriteFile(of, []byte(code), 0644))
+	}
+
+	assert.NoError(t, err)
+	assert.NotEmpty(t, code)
+
+	tfs := token.NewFileSet()
+	tfs.AddFile("petstore.gen.go", tfs.Base(), len(code))
+	cwd, _ := os.Getwd()
+	pkgs, err := packages.Load(&packages.Config{
+		Mode: packages.NeedSyntax | packages.NeedTypes | packages.NeedImports,
+		Fset: tfs,
+		Overlay: map[string][]byte{
+			cwd + "/petstore/petstore.gen.go": []byte(code),
+		},
+	}, "./petstore")
+	assert.NoError(t, err)
+	assert.Len(t, pkgs, 1)
+	pkg := pkgs[0]
+	assert.Empty(t, pkg.Errors)
+
+	// check we import the requests package
+	_, ok := pkg.Imports["github.com/carlmjohnson/requests"]
+	assert.True(t, ok)
+
+	client := pkg.Types.Scope().Lookup("Client")
+	assert.NotNil(t, client)
+
+	assert.True(t, client.Exported())
+	assert.Equal(t, client.Type().Underlying().(*types.Struct).NumFields(), 4)
+}

codegen/template_helpers.go

@@ -101,6 +101,16 @@ func responseNameToStatusCode(responseName string) string {
 	}
 }
 
+func responseToStatusRangeString(responseName string) string {
+	switch strings.ToUpper(responseName) {
+	case "DEFAULT":
+		return "resp.StatusCode != 0"
+	case "1XX", "2XX", "3XX", "4XX", "5XX":
+		return fmt.Sprintf("resp.StatusCode < %s00 && resp.StatusCode > %s99", responseName[:1], responseName[:1])
+	}
+	return fmt.Sprintf("resp.StatusCode != %s", responseName)
+}
+
 // TitleWord converts a single worded string to title case.
 // This is a replacement to `strings.Title` which we used previously.
 // We didn't need strings.Title word boundary rules, and just want to Title the words directly,
@@ -112,6 +122,11 @@ func TitleWord(s string) string {
 	return string(r)
 }
 
+// ToComment converts a string to a comment.
+func ToComment(s string) string {
+	return "// " + strings.ReplaceAll(s, "\n", "\n// ")
+}
+
 // TemplateFunctions generates the list of utlity and helpfer functions used by
 // the templates.
 var TemplateFunctions = template.FuncMap{
@@ -120,10 +135,12 @@ var TemplateFunctions = template.FuncMap{
 	"getResponseTypeDefinitions": getResponseTypeDefinitions,
 	"genTaggedMiddleware":        getTaggedMiddlewares,
 	"toStringArray":              toStringArray,
+	"toComment":                  ToComment,
 
 	"swaggerURIToChiURI": SwaggerURIToChiURI,
 
-	"statusCode": responseNameToStatusCode,
+	"statusCode":      responseNameToStatusCode,
+	"statusCodeRange": responseToStatusRangeString,
 
 	"ucFirst": snaker.ForceCamelIdentifier,
 	"lower":   strings.ToLower,