case-insensitive header comparison (#488)

README.md

@@ -31,6 +31,7 @@ docker run --rm -t tufin/oasdiff changelog https://raw.githubusercontent.com/Tuf
 - [Multiple versions of the same endpoint](MATCHING-ENDPOINTS.md)
 - [Merge allOf schemas](ALLOF.md)
 - [Merge common parameters](COMMON-PARAMS.md)
+- [Case-insensitive header comparison](#case-insensitive-header-comparison)
 - [Path prefix modification](#path-prefix-modification)
 - [Path parameter renaming](#path-parameter-renaming)
 - [Excluding certain kinds of changes](#excluding-specific-kinds-of-changes)
@@ -241,6 +242,13 @@ Sometimes developers decide to change names of path parameters, for example, in
 Oasdiff supports path parameter renaming by default.  
 [Learn more](MATCHING-ENDPOINTS.md) about how oasdiff supports path parameter renaming.
 
+## Case-Insensitive Header Comparison
+Header names comparison is normally case-sensitive.  
+To make this comparison case-insensitive, add the `--case-insensitive-headers` flag:
+```
+oasdiff diff data/header-case/base.yaml data/header-case/revision.yaml --case-insensitive-headers
+```
+
 ## Excluding Specific Kinds of Changes 
 You can use the `--exclude-elements` flag to exclude certain kinds of changes:
 - Use `--exclude-elements examples` to exclude [Examples](https://swagger.io/specification/#example-object)

data/header-case/base.yaml

@@ -0,0 +1,18 @@
+openapi: 3.0.1
+info:
+  title: Test API
+  version: v1
+paths:
+  /test:
+    parameters:
+      - in: header
+        name: X-Case
+        required: true
+        schema:
+          type: string
+    get:
+      tags:
+        - Test
+      responses:
+        "200":
+          description: Success

data/header-case/revision.yaml

@@ -0,0 +1,18 @@
+openapi: 3.0.1
+info:
+  title: Test API
+  version: v1
+paths:
+  /test:
+    parameters:
+      - in: header
+        name: x-case
+        required: true
+        schema:
+          type: string
+    get:
+      tags:
+        - Test
+      responses:
+        "200":
+          description: Success

flatten/headers/doc.go

@@ -0,0 +1,4 @@
+/*
+Package headers replaces all header names to lowercase
+*/
+package headers

flatten/headers/params.go

@@ -0,0 +1,41 @@
+package headers
+
+import (
+	"strings"
+
+	"github.com/getkin/kin-openapi/openapi3"
+)
+
+// Lowercase replaces header names to lowercase
+func Lowercase(spec *openapi3.T) {
+	lowerHeaderNames(spec)
+}
+
+func lowerHeaderNames(spec *openapi3.T) {
+	for _, path := range spec.Paths.Map() {
+
+		for _, paramRef := range path.Parameters {
+			lowerHeaderName(paramRef.Value)
+		}
+
+		for _, op := range path.Operations() {
+			for _, paramRef := range op.Parameters {
+				lowerHeaderName(paramRef.Value)
+			}
+
+			for _, responseRef := range op.Responses.Map() {
+				for _, headerRef := range responseRef.Value.Headers {
+					lowerHeaderName(&headerRef.Value.Parameter)
+				}
+			}
+		}
+	}
+}
+
+func lowerHeaderName(param *openapi3.Parameter) {
+	if param.In != openapi3.ParameterInHeader {
+		return
+	}
+
+	param.Name = strings.ToLower(param.Name)
+}

internal/changelog_flags.go

@@ -23,6 +23,7 @@ type ChangelogFlags struct {
 	failOn                   string
 	flattenAllOf             bool
 	flattenParams            bool
+	insensitiveHeaders       bool
 	lang                     string
 	errIgnoreFile            string
 	warnIgnoreFile           string
@@ -64,6 +65,10 @@ func (flags *ChangelogFlags) getFlattenParams() bool {
 	return flags.flattenParams
 }
 
+func (flags *ChangelogFlags) getInsensitiveHeaders() bool {
+	return flags.insensitiveHeaders
+}
+
 func (flags *ChangelogFlags) getCircularReferenceCounter() int {
 	return flags.circularReferenceCounter
 }
@@ -172,6 +177,10 @@ func (flags *ChangelogFlags) refFlattenParams() *bool {
 	return &flags.flattenParams
 }
 
+func (flags *ChangelogFlags) refInsensitiveHeaders() *bool {
+	return &flags.insensitiveHeaders
+}
+
 func (flags *ChangelogFlags) refLang() *string {
 	return &flags.lang
 }

internal/cmd_flags.go

@@ -20,6 +20,7 @@ func addCommonDiffFlags(cmd *cobra.Command, flags Flags) {
 	cmd.PersistentFlags().BoolVarP(flags.refIncludePathParams(), "include-path-params", "", false, "include path parameter names in endpoint matching")
 	cmd.PersistentFlags().BoolVarP(flags.refFlattenAllOf(), "flatten-allof", "", false, "merge subschemas under allOf before diff")
 	cmd.PersistentFlags().BoolVarP(flags.refFlattenParams(), "flatten-params", "", false, "merge common parameters at path level with operation parameters")
+	cmd.PersistentFlags().BoolVarP(flags.refInsensitiveHeaders(), "case-insensitive-headers", "", false, "case-insensitive header name comparison")
 	addDeprecatedFlattenFlag(cmd, flags)
 }
 

internal/delta_flags.go

@@ -56,3 +56,7 @@ func (flags *DeltaFlags) refFlattenAllOf() *bool {
 func (flags *DeltaFlags) refFlattenParams() *bool {
 	return &flags.flattenParams
 }
+
+func (flags *DeltaFlags) refInsensitiveHeaders() *bool {
+	return &flags.insensitiveHeaders
+}

internal/diff.go

@@ -99,13 +99,14 @@ func normalDiff(loader load.Loader, flags Flags) (*diffResult, *ReturnError) {
 
 	flattenAllOf := load.GetOption(load.WithFlattenAllOf(), flags.getFlattenAllOf())
 	flattenParams := load.GetOption(load.WithFlattenParams(), flags.getFlattenParams())
+	lowerHeaderNames := load.GetOption(load.WithLowercaseHeaders(), flags.getInsensitiveHeaders())
 
-	s1, err := load.NewSpecInfo(loader, flags.getBase(), flattenAllOf, flattenParams)
+	s1, err := load.NewSpecInfo(loader, flags.getBase(), flattenAllOf, flattenParams, lowerHeaderNames)
 	if err != nil {
 		return nil, getErrFailedToLoadSpec("base", flags.getBase(), err)
 	}
 
-	s2, err := load.NewSpecInfo(loader, flags.getRevision(), flattenAllOf, flattenParams)
+	s2, err := load.NewSpecInfo(loader, flags.getRevision(), flattenAllOf, flattenParams, lowerHeaderNames)
 	if err != nil {
 		return nil, getErrFailedToLoadSpec("revision", flags.getRevision(), err)
 	}
@@ -127,13 +128,14 @@ func composedDiff(loader load.Loader, flags Flags) (*diffResult, *ReturnError) {
 
 	flattenAllOf := load.GetOption(load.WithFlattenAllOf(), flags.getFlattenAllOf())
 	flattenParams := load.GetOption(load.WithFlattenParams(), flags.getFlattenParams())
+	lowerHeaderNames := load.GetOption(load.WithLowercaseHeaders(), flags.getInsensitiveHeaders())
 
-	s1, err := load.NewSpecInfoFromGlob(loader, flags.getBase().Path, flattenAllOf, flattenParams)
+	s1, err := load.NewSpecInfoFromGlob(loader, flags.getBase().Path, flattenAllOf, flattenParams, lowerHeaderNames)
 	if err != nil {
 		return nil, getErrFailedToLoadSpecs("base", flags.getBase().Path, err)
 	}
 
-	s2, err := load.NewSpecInfoFromGlob(loader, flags.getRevision().Path, flattenAllOf, flattenParams)
+	s2, err := load.NewSpecInfoFromGlob(loader, flags.getRevision().Path, flattenAllOf, flattenParams, lowerHeaderNames)
 	if err != nil {
 		return nil, getErrFailedToLoadSpecs("revision", flags.getRevision().Path, err)
 	}

internal/diff_flags.go

@@ -19,6 +19,7 @@ type DiffFlags struct {
 	failOnDiff               bool
 	flattenAllOf             bool
 	flattenParams            bool
+	insensitiveHeaders       bool
 	circularReferenceCounter int
 	includePathParams        bool
 	excludeElements          []string
@@ -57,6 +58,10 @@ func (flags *DiffFlags) getFlattenParams() bool {
 	return flags.flattenParams
 }
 
+func (flags *DiffFlags) getInsensitiveHeaders() bool {
+	return flags.insensitiveHeaders
+}
+
 func (flags *DiffFlags) getCircularReferenceCounter() int {
 	return flags.circularReferenceCounter
 }
@@ -165,6 +170,10 @@ func (flags *DiffFlags) refFlattenParams() *bool {
 	return &flags.flattenParams
 }
 
+func (flags *DiffFlags) refInsensitiveHeaders() *bool {
+	return &flags.insensitiveHeaders
+}
+
 func (flags *DiffFlags) refLang() *string {
 	return nil
 }

internal/flags.go

@@ -13,6 +13,7 @@ type Flags interface {
 	getRevision() *load.Source
 	getFlattenAllOf() bool
 	getFlattenParams() bool
+	getInsensitiveHeaders() bool
 	getCircularReferenceCounter() int
 	getIncludeChecks() []string
 	getDeprecationDaysBeta() int
@@ -43,6 +44,7 @@ type Flags interface {
 	refIncludePathParams() *bool
 	refFlattenAllOf() *bool
 	refFlattenParams() *bool
+	refInsensitiveHeaders() *bool
 	refLang() *string
 	refErrIgnoreFile() *string
 	refWarnIgnoreFile() *string

internal/run_test.go

@@ -274,6 +274,10 @@ func Test_BreakingChangesFlattenCommonParams(t *testing.T) {
 	require.Zero(t, internal.Run(cmdToArgs("oasdiff breaking ../data/common-params/params_in_path.yaml ../data/common-params/params_in_op.yaml --flatten-params --fail-on ERR"), io.Discard, io.Discard))
 }
 
+func Test_BreakingChangesCaseInsensitiveHeaders(t *testing.T) {
+	require.Zero(t, internal.Run(cmdToArgs("oasdiff breaking ../data/header-case/base.yaml ../data/header-case/revision.yaml --case-insensitive-headers --fail-on ERR"), io.Discard, io.Discard))
+}
+
 func Test_FlattenCmdOK(t *testing.T) {
 	require.Zero(t, internal.Run(cmdToArgs("oasdiff flatten ../data/allof/simple.yaml"), io.Discard, io.Discard))
 }

load/option.go

@@ -3,6 +3,7 @@ package load
 import (
 	"github.com/tufin/oasdiff/flatten/allof"
 	"github.com/tufin/oasdiff/flatten/commonparams"
+	"github.com/tufin/oasdiff/flatten/headers"
 )
 
 // option functions can be used to preprocess specs after loading them
@@ -46,3 +47,13 @@ func WithFlattenParams() Option {
 		return specInfos, nil
 	}
 }
+
+// WithLowercaseHeaders returns SpecInfos with header names converted to lowercase
+func WithLowercaseHeaders() Option {
+	return func(loader Loader, specInfos []*SpecInfo) ([]*SpecInfo, error) {
+		for _, specInfo := range specInfos {
+			headers.Lowercase(specInfo.Spec)
+		}
+		return specInfos, nil
+	}
+}