// Copyright 2015 go-swagger maintainers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package analysis
import (
"fmt"
"log"
"path"
"sort"
"strings"
"github.com/go-openapi/analysis/internal/flatten/normalize"
"github.com/go-openapi/analysis/internal/flatten/operations"
"github.com/go-openapi/analysis/internal/flatten/replace"
"github.com/go-openapi/analysis/internal/flatten/schutils"
"github.com/go-openapi/analysis/internal/flatten/sortref"
"github.com/go-openapi/jsonpointer"
"github.com/go-openapi/spec"
)
const definitionsPath = "#/definitions"
// newRef stores information about refs created during the flattening process
type newRef struct {
key string
newName string
path string
isOAIGen bool
resolved bool
schema *spec.Schema
parents []string
}
// context stores intermediary results from flatten
type context struct {
newRefs map[string]*newRef
warnings []string
resolved map[string]string
}
func newContext() *context {
return &context{
newRefs: make(map[string]*newRef, 150),
warnings: make([]string, 0),
resolved: make(map[string]string, 50),
}
}
// Flatten an analyzed spec and produce a self-contained spec bundle.
//
// There is a minimal and a full flattening mode.
//
//
// Minimally flattening a spec means:
// - Expanding parameters, responses, path items, parameter items and header items (references to schemas are left
// unscathed)
// - Importing external (http, file) references so they become internal to the document
// - Moving every JSON pointer to a $ref to a named definition (i.e. the reworked spec does not contain pointers
// like "$ref": "#/definitions/myObject/allOfs/1")
//
// A minimally flattened spec thus guarantees the following properties:
// - all $refs point to a local definition (i.e. '#/definitions/...')
// - definitions are unique
//
// NOTE: arbitrary JSON pointers (other than $refs to top level definitions) are rewritten as definitions if they
// represent a complex schema or express commonality in the spec.
// Otherwise, they are simply expanded.
// Self-referencing JSON pointers cannot resolve to a type and trigger an error.
//
//
// Minimal flattening is necessary and sufficient for codegen rendering using go-swagger.
//
// Fully flattening a spec means:
// - Moving every complex inline schema to be a definition with an auto-generated name in a depth-first fashion.
//
// By complex, we mean every JSON object with some properties.
// Arrays, when they do not define a tuple,
// or empty objects with or without additionalProperties, are not considered complex and remain inline.
//
// NOTE: rewritten schemas get a vendor extension x-go-gen-location so we know from which part of the spec definitions
// have been created.
//
// Available flattening options:
// - Minimal: stops flattening after minimal $ref processing, leaving schema constructs untouched
// - Expand: expand all $ref's in the document (inoperant if Minimal set to true)
// - Verbose: croaks about name conflicts detected
// - RemoveUnused: removes unused parameters, responses and definitions after expansion/flattening
//
// NOTE: expansion removes all $ref save circular $ref, which remain in place
//
// TODO: additional options
// - ProgagateNameExtensions: ensure that created entries properly follow naming rules when their parent have set a
// x-go-name extension
// - LiftAllOfs:
// - limit the flattening of allOf members when simple objects
// - merge allOf with validation only
// - merge allOf with extensions only
// - ...
//
func Flatten(opts FlattenOpts) error {
debugLog("FlattenOpts: %#v", opts)
opts.flattenContext = newContext()
// 1. Recursively expand responses, parameters, path items and items in simple schemas.
//
// This simplifies the spec and leaves only the $ref's in schema objects.
if err := expand(&opts); err != nil {
return err
}
// 2. Strip the current document from absolute $ref's that actually a in the root,
// so we can recognize them as proper definitions
//
// In particular, this works around issue go-openapi/spec#76: leading absolute file in $ref is stripped
if err := normalizeRef(&opts); err != nil {
return err
}
// 3. Optionally remove shared parameters and responses already expanded (now unused).
//
// Operation parameters (i.e. under paths) remain.
if opts.RemoveUnused {
removeUnusedShared(&opts)
}
// 4. Import all remote references.
if err := importReferences(&opts); err != nil {
return err
}
// 5. full flattening: rewrite inline schemas (schemas that aren't simple types or arrays or maps)
if !opts.Minimal && !opts.Expand {
if err := nameInlinedSchemas(&opts); err != nil {
return err
}
}
// 6. Rewrite JSON pointers other than $ref to named definitions
// and attempt to resolve conflicting names whenever possible.
if err := stripPointersAndOAIGen(&opts); err != nil {
return err
}
// 7. Strip the spec from unused definitions
if opts.RemoveUnused {
removeUnused(&opts)
}
// 8. Issue warning notifications, if any
opts.croak()
// TODO: simplify known schema patterns to flat objects with properties
// examples:
// - lift simple allOf object,
// - empty allOf with validation only or extensions only
// - rework allOf arrays
// - rework allOf additionalProperties
return nil
}
func expand(opts *FlattenOpts) error {
if err := spec.ExpandSpec(opts.Swagger(), opts.ExpandOpts(!opts.Expand)); err != nil {
return err
}
opts.Spec.reload() // re-analyze
return nil
}
// normalizeRef strips the current file from any absolute file $ref. This works around issue go-openapi/spec#76:
// leading absolute file in $ref is stripped
func normalizeRef(opts *FlattenOpts) error {
debugLog("normalizeRef")
altered := false
for k, w := range opts.Spec.references.allRefs {
if !strings.HasPrefix(w.String(), opts.BasePath+definitionsPath) { // may be a mix of / and \, depending on OS
continue
}
altered = true
debugLog("stripping absolute path for: %s", w.String())
// strip the base path from definition
if err := replace.UpdateRef(opts.Swagger(), k,
spec.MustCreateRef(path.Join(definitionsPath, path.Base(w.String())))); err != nil {
return err
}
}
if altered {
opts.Spec.reload() // re-analyze
}
return nil
}
func removeUnusedShared(opts *FlattenOpts) {
opts.Swagger().Parameters = nil
opts.Swagger().Responses = nil
opts.Spec.reload() // re-analyze
}
func importReferences(opts *FlattenOpts) error {
var (
imported bool
err error
)
for !imported && err == nil {
// iteratively import remote references until none left.
// This inlining deals with name conflicts by introducing auto-generated names ("OAIGen")
imported, err = importExternalReferences(opts)
opts.Spec.reload() // re-analyze
}
return err
}
// nameInlinedSchemas replaces every complex inline construct by a named definition.
func nameInlinedSchemas(opts *FlattenOpts) error {
debugLog("nameInlinedSchemas")
namer := &InlineSchemaNamer{
Spec: opts.Swagger(),
Operations: operations.AllOpRefsByRef(opts.Spec, nil),
flattenContext: opts.flattenContext,
opts: opts,
}
depthFirst := sortref.DepthFirst(opts.Spec.allSchemas)
for _, key := range depthFirst {
sch := opts.Spec.allSchemas[key]
if sch.Schema == nil || sch.Schema.Ref.String() != "" || sch.TopLevel {
continue
}
asch, err := Schema(SchemaOpts{Schema: sch.Schema, Root: opts.Swagger(), BasePath: opts.BasePath})
if err != nil {
return fmt.Errorf("schema analysis [%s]: %w", key, err)
}
if asch.isAnalyzedAsComplex() { // move complex schemas to definitions
if err := namer.Name(key, sch.Schema, asch); err != nil {
return err
}
}
}
opts.Spec.reload() // re-analyze
return nil
}
func removeUnused(opts *FlattenOpts) {
expected := make(map[string]struct{})
for k := range opts.Swagger().Definitions {
expected[path.Join(definitionsPath, jsonpointer.Escape(k))] = struct{}{}
}
for _, k := range opts.Spec.AllDefinitionReferences() {
delete(expected, k)
}
for k := range expected {
debugLog("removing unused definition %s", path.Base(k))
if opts.Verbose {
log.Printf("info: removing unused definition: %s", path.Base(k))
}
delete(opts.Swagger().Definitions, path.Base(k))
}
opts.Spec.reload() // re-analyze
}
func importKnownRef(entry sortref.RefRevIdx, refStr, newName string, opts *FlattenOpts) error {
// rewrite ref with already resolved external ref (useful for cyclical refs):
// rewrite external refs to local ones
debugLog("resolving known ref [%s] to %s", refStr, newName)
for _, key := range entry.Keys {
if err := replace.UpdateRef(opts.Swagger(), key, spec.MustCreateRef(path.Join(definitionsPath, newName))); err != nil {
return err
}
}
return nil
}
func importNewRef(entry sortref.RefRevIdx, refStr string, opts *FlattenOpts) error {
var (
isOAIGen bool
newName string
)
debugLog("resolving schema from remote $ref [%s]", refStr)
sch, err := spec.ResolveRefWithBase(opts.Swagger(), &entry.Ref, opts.ExpandOpts(false))
if err != nil {
return fmt.Errorf("could not resolve schema: %w", err)
}
// at this stage only $ref analysis matters
partialAnalyzer := &Spec{
references: referenceAnalysis{},
patterns: patternAnalysis{},
enums: enumAnalysis{},
}
partialAnalyzer.reset()
partialAnalyzer.analyzeSchema("", sch, "/")
// now rewrite those refs with rebase
for key, ref := range partialAnalyzer.references.allRefs {
if err := replace.UpdateRef(sch, key, spec.MustCreateRef(normalize.RebaseRef(entry.Ref.String(), ref.String()))); err != nil {
return fmt.Errorf("failed to rewrite ref for key %q at %s: %w", key, entry.Ref.String(), err)
}
}
// generate a unique name - isOAIGen means that a naming conflict was resolved by changing the name
newName, isOAIGen = uniqifyName(opts.Swagger().Definitions, nameFromRef(entry.Ref))
debugLog("new name for [%s]: %s - with name conflict:%t", strings.Join(entry.Keys, ", "), newName, isOAIGen)
opts.flattenContext.resolved[refStr] = newName
// rewrite the external refs to local ones
for _, key := range entry.Keys {
if err := replace.UpdateRef(opts.Swagger(), key,
spec.MustCreateRef(path.Join(definitionsPath, newName))); err != nil {
return err
}
// keep track of created refs
resolved := false
if _, ok := opts.flattenContext.newRefs[key]; ok {
resolved = opts.flattenContext.newRefs[key].resolved
}
debugLog("keeping track of ref: %s (%s), resolved: %t", key, newName, resolved)
opts.flattenContext.newRefs[key] = &newRef{
key: key,
newName: newName,
path: path.Join(definitionsPath, newName),
isOAIGen: isOAIGen,
resolved: resolved,
schema: sch,
}
}
// add the resolved schema to the definitions
schutils.Save(opts.Swagger(), newName, sch)
return nil
}
// importExternalReferences iteratively digs remote references and imports them into the main schema.
//
// At every iteration, new remotes may be found when digging deeper: they are rebased to the current schema before being imported.
//
// This returns true when no more remote references can be found.
func importExternalReferences(opts *FlattenOpts) (bool, error) {
debugLog("importExternalReferences")
groupedRefs := sortref.ReverseIndex(opts.Spec.references.schemas, opts.BasePath)
sortedRefStr := make([]string, 0, len(groupedRefs))
if opts.flattenContext == nil {
opts.flattenContext = newContext()
}
// sort $ref resolution to ensure deterministic name conflict resolution
for refStr := range groupedRefs {
sortedRefStr = append(sortedRefStr, refStr)
}
sort.Strings(sortedRefStr)
complete := true
for _, refStr := range sortedRefStr {
entry := groupedRefs[refStr]
if entry.Ref.HasFragmentOnly {
continue
}
complete = false
newName := opts.flattenContext.resolved[refStr]
if newName != "" {
if err := importKnownRef(entry, refStr, newName, opts); err != nil {
return false, err
}
continue
}
// resolve schemas
if err := importNewRef(entry, refStr, opts); err != nil {
return false, err
}
}
// maintains ref index entries
for k := range opts.flattenContext.newRefs {
r := opts.flattenContext.newRefs[k]
// update tracking with resolved schemas
if r.schema.Ref.String() != "" {
ref := spec.MustCreateRef(r.path)
sch, err := spec.ResolveRefWithBase(opts.Swagger(), &ref, opts.ExpandOpts(false))
if err != nil {
return false, fmt.Errorf("could not resolve schema: %w", err)
}
r.schema = sch
}
if r.path == k {
continue
}
// update tracking with renamed keys: got a cascade of refs
renamed := *r
renamed.key = r.path
opts.flattenContext.newRefs[renamed.path] = &renamed
// indirect ref
r.newName = path.Base(k)
r.schema = spec.RefSchema(r.path)
r.path = k
r.isOAIGen = strings.Contains(k, "OAIGen")
}
return complete, nil
}
// stripPointersAndOAIGen removes anonymous JSON pointers from spec and chain with name conflicts handler.
// This loops until the spec has no such pointer and all name conflicts have been reduced as much as possible.
func stripPointersAndOAIGen(opts *FlattenOpts) error {
// name all JSON pointers to anonymous documents
if err := namePointers(opts); err != nil {
return err
}
// remove unnecessary OAIGen ref (created when flattening external refs creates name conflicts)
hasIntroducedPointerOrInline, ers := stripOAIGen(opts)
if ers != nil {
return ers
}
// iterate as pointer or OAIGen resolution may introduce inline schemas or pointers
for hasIntroducedPointerOrInline {
if !opts.Minimal {
opts.Spec.reload() // re-analyze
if err := nameInlinedSchemas(opts); err != nil {
return err
}
}
if err := namePointers(opts); err != nil {
return err
}
// restrip and re-analyze
var err error
if hasIntroducedPointerOrInline, err = stripOAIGen(opts); err != nil {
return err
}
}
return nil
}
// stripOAIGen strips the spec from unnecessary OAIGen constructs, initially created to dedupe flattened definitions.
//
// A dedupe is deemed unnecessary whenever:
// - the only conflict is with its (single) parent: OAIGen is merged into its parent (reinlining)
// - there is a conflict with multiple parents: merge OAIGen in first parent, the rewrite other parents to point to
// the first parent.
//
// This function returns true whenever it re-inlined a complex schema, so the caller may chose to iterate
// pointer and name resolution again.
func stripOAIGen(opts *FlattenOpts) (bool, error) {
debugLog("stripOAIGen")
replacedWithComplex := false
// figure out referers of OAIGen definitions (doing it before the ref start mutating)
for _, r := range opts.flattenContext.newRefs {
updateRefParents(opts.Spec.references.allRefs, r)
}
for k := range opts.flattenContext.newRefs {
r := opts.flattenContext.newRefs[k]
debugLog("newRefs[%s]: isOAIGen: %t, resolved: %t, name: %s, path:%s, #parents: %d, parents: %v, ref: %s",
k, r.isOAIGen, r.resolved, r.newName, r.path, len(r.parents), r.parents, r.schema.Ref.String())
if !r.isOAIGen || len(r.parents) == 0 {
continue
}
hasReplacedWithComplex, err := stripOAIGenForRef(opts, k, r)
if err != nil {
return replacedWithComplex, err
}
replacedWithComplex = replacedWithComplex || hasReplacedWithComplex
}
debugLog("replacedWithComplex: %t", replacedWithComplex)
opts.Spec.reload() // re-analyze
return replacedWithComplex, nil
}
// updateRefParents updates all parents of an updated $ref
func updateRefParents(allRefs map[string]spec.Ref, r *newRef) {
if !r.isOAIGen || r.resolved { // bail on already resolved entries (avoid looping)
return
}
for k, v := range allRefs {
if r.path != v.String() {
continue
}
found := false
for _, p := range r.parents {
if p == k {
found = true
break
}
}
if !found {
r.parents = append(r.parents, k)
}
}
}
func stripOAIGenForRef(opts *FlattenOpts, k string, r *newRef) (bool, error) {
replacedWithComplex := false
pr := sortref.TopmostFirst(r.parents)
// rewrite first parent schema in hierarchical then lexicographical order
debugLog("rewrite first parent %s with schema", pr[0])
if err := replace.UpdateRefWithSchema(opts.Swagger(), pr[0], r.schema); err != nil {
return false, err
}
if pa, ok := opts.flattenContext.newRefs[pr[0]]; ok && pa.isOAIGen {
// update parent in ref index entry
debugLog("update parent entry: %s", pr[0])
pa.schema = r.schema
pa.resolved = false
replacedWithComplex = true
}
// rewrite other parents to point to first parent
if len(pr) > 1 {
for _, p := range pr[1:] {
replacingRef := spec.MustCreateRef(pr[0])
// set complex when replacing ref is an anonymous jsonpointer: further processing may be required
replacedWithComplex = replacedWithComplex || path.Dir(replacingRef.String()) != definitionsPath
debugLog("rewrite parent with ref: %s", replacingRef.String())
// NOTE: it is possible at this stage to introduce json pointers (to non-definitions places).
// Those are stripped later on.
if err := replace.UpdateRef(opts.Swagger(), p, replacingRef); err != nil {
return false, err
}
if pa, ok := opts.flattenContext.newRefs[p]; ok && pa.isOAIGen {
// update parent in ref index
debugLog("update parent entry: %s", p)
pa.schema = r.schema
pa.resolved = false
replacedWithComplex = true
}
}
}
// remove OAIGen definition
debugLog("removing definition %s", path.Base(r.path))
delete(opts.Swagger().Definitions, path.Base(r.path))
// propagate changes in ref index for keys which have this one as a parent
for kk, value := range opts.flattenContext.newRefs {
if kk == k || !value.isOAIGen || value.resolved {
continue
}
found := false
newParents := make([]string, 0, len(value.parents))
for _, parent := range value.parents {
switch {
case parent == r.path:
found = true
parent = pr[0]
case strings.HasPrefix(parent, r.path+"/"):
found = true
parent = path.Join(pr[0], strings.TrimPrefix(parent, r.path))
}
newParents = append(newParents, parent)
}
if found {
value.parents = newParents
}
}
// mark naming conflict as resolved
debugLog("marking naming conflict resolved for key: %s", r.key)
opts.flattenContext.newRefs[r.key].isOAIGen = false
opts.flattenContext.newRefs[r.key].resolved = true
// determine if the previous substitution did inline a complex schema
if r.schema != nil && r.schema.Ref.String() == "" { // inline schema
asch, err := Schema(SchemaOpts{Schema: r.schema, Root: opts.Swagger(), BasePath: opts.BasePath})
if err != nil {
return false, err
}
debugLog("re-inlined schema: parent: %s, %t", pr[0], asch.isAnalyzedAsComplex())
replacedWithComplex = replacedWithComplex || !(path.Dir(pr[0]) == definitionsPath) && asch.isAnalyzedAsComplex()
}
return replacedWithComplex, nil
}
// namePointers replaces all JSON pointers to anonymous documents by a $ref to a new named definitions.
//
// This is carried on depth-first. Pointers to $refs which are top level definitions are replaced by the $ref itself.
// Pointers to simple types are expanded, unless they express commonality (i.e. several such $ref are used).
func namePointers(opts *FlattenOpts) error {
debugLog("name pointers")
refsToReplace := make(map[string]SchemaRef, len(opts.Spec.references.schemas))
for k, ref := range opts.Spec.references.allRefs {
if path.Dir(ref.String()) == definitionsPath {
// this a ref to a top-level definition: ok
continue
}
result, err := replace.DeepestRef(opts.Swagger(), opts.ExpandOpts(false), ref)
if err != nil {
return fmt.Errorf("at %s, %w", k, err)
}
replacingRef := result.Ref
sch := result.Schema
if opts.flattenContext != nil {
opts.flattenContext.warnings = append(opts.flattenContext.warnings, result.Warnings...)
}
debugLog("planning pointer to replace at %s: %s, resolved to: %s", k, ref.String(), replacingRef.String())
refsToReplace[k] = SchemaRef{
Name: k, // caller
Ref: replacingRef, // called
Schema: sch,
TopLevel: path.Dir(replacingRef.String()) == definitionsPath,
}
}
depthFirst := sortref.DepthFirst(refsToReplace)
namer := &InlineSchemaNamer{
Spec: opts.Swagger(),
Operations: operations.AllOpRefsByRef(opts.Spec, nil),
flattenContext: opts.flattenContext,
opts: opts,
}
for _, key := range depthFirst {
v := refsToReplace[key]
// update current replacement, which may have been updated by previous changes of deeper elements
result, erd := replace.DeepestRef(opts.Swagger(), opts.ExpandOpts(false), v.Ref)
if erd != nil {
return fmt.Errorf("at %s, %w", key, erd)
}
if opts.flattenContext != nil {
opts.flattenContext.warnings = append(opts.flattenContext.warnings, result.Warnings...)
}
v.Ref = result.Ref
v.Schema = result.Schema
v.TopLevel = path.Dir(result.Ref.String()) == definitionsPath
debugLog("replacing pointer at %s: resolved to: %s", key, v.Ref.String())
if v.TopLevel {
debugLog("replace pointer %s by canonical definition: %s", key, v.Ref.String())
// if the schema is a $ref to a top level definition, just rewrite the pointer to this $ref
if err := replace.UpdateRef(opts.Swagger(), key, v.Ref); err != nil {
return err
}
continue
}
if err := flattenAnonPointer(key, v, refsToReplace, namer, opts); err != nil {
return err
}
}
opts.Spec.reload() // re-analyze
return nil
}
func flattenAnonPointer(key string, v SchemaRef, refsToReplace map[string]SchemaRef, namer *InlineSchemaNamer, opts *FlattenOpts) error {
// this is a JSON pointer to an anonymous document (internal or external):
// create a definition for this schema when:
// - it is a complex schema
// - or it is pointed by more than one $ref (i.e. expresses commonality)
// otherwise, expand the pointer (single reference to a simple type)
//
// The named definition for this follows the target's key, not the caller's
debugLog("namePointers at %s for %s", key, v.Ref.String())
// qualify the expanded schema
asch, ers := Schema(SchemaOpts{Schema: v.Schema, Root: opts.Swagger(), BasePath: opts.BasePath})
if ers != nil {
return fmt.Errorf("schema analysis [%s]: %w", key, ers)
}
callers := make([]string, 0, 64)
debugLog("looking for callers")
an := New(opts.Swagger())
for k, w := range an.references.allRefs {
r, err := replace.DeepestRef(opts.Swagger(), opts.ExpandOpts(false), w)
if err != nil {
return fmt.Errorf("at %s, %w", key, err)
}
if opts.flattenContext != nil {
opts.flattenContext.warnings = append(opts.flattenContext.warnings, r.Warnings...)
}
if r.Ref.String() == v.Ref.String() {
callers = append(callers, k)
}
}
debugLog("callers for %s: %d", v.Ref.String(), len(callers))
if len(callers) == 0 {
// has already been updated and resolved
return nil
}
parts := sortref.KeyParts(v.Ref.String())
debugLog("number of callers for %s: %d", v.Ref.String(), len(callers))
// identifying edge case when the namer did nothing because we point to a non-schema object
// no definition is created and we expand the $ref for all callers
if (!asch.IsSimpleSchema || len(callers) > 1) && !parts.IsSharedParam() && !parts.IsSharedResponse() {
debugLog("replace JSON pointer at [%s] by definition: %s", key, v.Ref.String())
if err := namer.Name(v.Ref.String(), v.Schema, asch); err != nil {
return err
}
// regular case: we named the $ref as a definition, and we move all callers to this new $ref
for _, caller := range callers {
if caller == key {
continue
}
// move $ref for next to resolve
debugLog("identified caller of %s at [%s]", v.Ref.String(), caller)
c := refsToReplace[caller]
c.Ref = v.Ref
refsToReplace[caller] = c
}
return nil
}
debugLog("expand JSON pointer for key=%s", key)
if err := replace.UpdateRefWithSchema(opts.Swagger(), key, v.Schema); err != nil {
return err
}
// NOTE: there is no other caller to update
return nil
}