forked from goadesign/goa
/
types.go
1053 lines (926 loc) · 32 KB
/
types.go
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// Package design defines types which describe the data types used by action controllers.
// These are the data structures of the request payloads and parameters as well as the response
// payloads.
// There are primitive types corresponding to the JSON primitive types (bool, string, integer and
// number), array types which represent a collection of another type and object types corresponding
// to JSON objects (i.e. a map indexed by strings where each value may be any of the data types).
// On top of these the package also defines "user types" and "media types". Both these types are
// named objects with additional properties (a description and for media types the media type
// identifier, links and views).
package design
import (
"fmt"
"mime"
"reflect"
"sort"
"strings"
"time"
"github.com/goadesign/goa/dslengine"
"github.com/satori/go.uuid"
)
// DefaultView is the name of the default view.
const DefaultView = "default"
// It returns the default view - or if not available the link view - or if not available the first
// view by alphabetical order.
type (
// A Kind defines the JSON type that a DataType represents.
Kind uint
// DataType is the common interface to all types.
DataType interface {
// Kind of data type, one of the Kind enum.
Kind() Kind
// Name returns the type name.
Name() string
// IsPrimitive returns true if the underlying type is one of the primitive types.
IsPrimitive() bool
// HasAttributes returns true if the underlying type has any attributes.
HasAttributes() bool
// IsObject returns true if the underlying type is an object, a user type which
// is an object or a media type whose type is an object.
IsObject() bool
// IsArray returns true if the underlying type is an array, a user type which
// is an array or a media type whose type is an array.
IsArray() bool
// IsHash returns true if the underlying type is a hash map, a user type which
// is a hash map or a media type whose type is a hash map.
IsHash() bool
// ToObject returns the underlying object if any (i.e. if IsObject returns true),
// nil otherwise.
ToObject() Object
// ToArray returns the underlying array if any (i.e. if IsArray returns true),
// nil otherwise.
ToArray() *Array
// ToHash returns the underlying hash map if any (i.e. if IsHash returns true),
// nil otherwise.
ToHash() *Hash
// CanHaveDefault returns whether the data type can have a default value.
CanHaveDefault() bool
// IsCompatible checks whether val has a Go type that is
// compatible with the data type.
IsCompatible(val interface{}) bool
// GenerateExample returns a random value for the given data type.
// If the data type has validations then the example value validates them.
// seen keeps track of the user and media types that have been traversed via
// recursion to prevent infinite loops.
GenerateExample(r *RandomGenerator, seen []string) interface{}
}
// DataStructure is the interface implemented by all data structure types.
// That is attribute definitions, user types and media types.
DataStructure interface {
// Definition returns the data structure definition.
Definition() *AttributeDefinition
// Walk traverses the data structure recursively and calls the given function once
// on each attribute starting with the attribute returned by Definition.
// User type and media type attributes are traversed once even for recursive
// definitions to avoid infinite recursion.
// Walk stops and returns the error if the function returns a non-nil error.
Walk(func(*AttributeDefinition) error) error
}
// Primitive is the type for null, boolean, integer, number, string, and time.
Primitive Kind
// Array is the type for a JSON array.
Array struct {
ElemType *AttributeDefinition
}
// ArrayVal is the value of an array used to specify the default value.
ArrayVal []interface{}
// Object is the type for a JSON object.
Object map[string]*AttributeDefinition
// Hash is the type for a hash map.
Hash struct {
KeyType *AttributeDefinition
ElemType *AttributeDefinition
}
// HashVal is the value of a hash used to specify the default value.
HashVal map[interface{}]interface{}
// UserTypeDefinition is the type for user defined types that are not media types
// (e.g. payload types).
UserTypeDefinition struct {
// A user type is an attribute definition.
*AttributeDefinition
// Name of type
TypeName string
}
// MediaTypeDefinition describes the rendering of a resource using property and link
// definitions. A property corresponds to a single member of the media type,
// it has a name and a type as well as optional validation rules. A link has a
// name and a URL that points to a related resource.
// Media types also define views which describe which members and links to render when
// building the response body for the corresponding view.
MediaTypeDefinition struct {
// A media type is a type
*UserTypeDefinition
// Identifier is the RFC 6838 media type identifier.
Identifier string
// ContentType identifies the value written to the response "Content-Type" header.
// Defaults to Identifier.
ContentType string
// Links list the rendered links indexed by name.
Links map[string]*LinkDefinition
// Views list the supported views indexed by name.
Views map[string]*ViewDefinition
// Resource this media type is the canonical representation for if any
Resource *ResourceDefinition
}
)
const (
// BooleanKind represents a JSON bool.
BooleanKind Kind = iota + 1
// IntegerKind represents a JSON integer.
IntegerKind
// NumberKind represents a JSON number including integers.
NumberKind
// StringKind represents a JSON string.
StringKind
// DateTimeKind represents a JSON string that is parsed as a Go time.Time
DateTimeKind
// UUIDKind represents a JSON string that is parsed as a Go uuid.UUID
UUIDKind
// AnyKind represents a generic interface{}.
AnyKind
// ArrayKind represents a JSON array.
ArrayKind
// ObjectKind represents a JSON object.
ObjectKind
// HashKind represents a JSON object where the keys are not known in advance.
HashKind
// UserTypeKind represents a user type.
UserTypeKind
// MediaTypeKind represents a media type.
MediaTypeKind
)
const (
// Boolean is the type for a JSON boolean.
Boolean = Primitive(BooleanKind)
// Integer is the type for a JSON number without a fraction or exponent part.
Integer = Primitive(IntegerKind)
// Number is the type for any JSON number, including integers.
Number = Primitive(NumberKind)
// String is the type for a JSON string.
String = Primitive(StringKind)
// DateTime is the type for a JSON string parsed as a Go time.Time
// DateTime expects an RFC3339 formatted value.
DateTime = Primitive(DateTimeKind)
// UUID is the type for a JSON string parsed as a Go uuid.UUID
// UUID expects an RFC4122 formatted value.
UUID = Primitive(UUIDKind)
// Any is the type for an arbitrary JSON value (interface{} in Go).
Any = Primitive(AnyKind)
)
// DataType implementation
// Kind implements DataKind.
func (p Primitive) Kind() Kind { return Kind(p) }
// Name returns the JSON type name.
func (p Primitive) Name() string {
switch p {
case Boolean:
return "boolean"
case Integer:
return "integer"
case Number:
return "number"
case String, DateTime, UUID:
return "string"
case Any:
return "any"
default:
panic("unknown primitive type") // bug
}
}
// IsPrimitive returns true.
func (p Primitive) IsPrimitive() bool { return true }
// HasAttributes returns false.
func (p Primitive) HasAttributes() bool { return false }
// IsObject returns false.
func (p Primitive) IsObject() bool { return false }
// IsArray returns false.
func (p Primitive) IsArray() bool { return false }
// IsHash returns false.
func (p Primitive) IsHash() bool { return false }
// ToObject returns nil.
func (p Primitive) ToObject() Object { return nil }
// ToArray returns nil.
func (p Primitive) ToArray() *Array { return nil }
// ToHash returns nil.
func (p Primitive) ToHash() *Hash { return nil }
// CanHaveDefault returns whether the primitive can have a default value.
func (p Primitive) CanHaveDefault() (ok bool) {
switch p {
case Boolean, Integer, Number, String, DateTime:
ok = true
}
return
}
// IsCompatible returns true if val is compatible with p.
func (p Primitive) IsCompatible(val interface{}) bool {
if p != Boolean && p != Integer && p != Number && p != String && p != DateTime && p != UUID && p != Any {
panic("unknown primitive type") // bug
}
if p == Any {
return true
}
switch val.(type) {
case bool:
return p == Boolean
case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
return p == Integer || p == Number
case float32, float64:
return p == Number
case string:
if p == String {
return true
}
if p == DateTime {
_, err := time.Parse(time.RFC3339, val.(string))
return err == nil
}
if p == UUID {
_, err := uuid.FromString(val.(string))
return err == nil
}
}
return false
}
var anyPrimitive = []Primitive{Boolean, Integer, Number, DateTime, UUID}
// GenerateExample returns an instance of the given data type.
func (p Primitive) GenerateExample(r *RandomGenerator, seen []string) interface{} {
switch p {
case Boolean:
return r.Bool()
case Integer:
return r.Int()
case Number:
return r.Float64()
case String:
return r.String()
case DateTime:
return r.DateTime()
case UUID:
return r.UUID().String() // Generate string to can be JSON marshaled
case Any:
// to not make it too complicated, pick one of the primitive types
return anyPrimitive[r.Int()%len(anyPrimitive)].GenerateExample(r, seen)
default:
panic("unknown primitive type") // bug
}
}
// Kind implements DataKind.
func (a *Array) Kind() Kind { return ArrayKind }
// Name returns the type name.
func (a *Array) Name() string {
return "array"
}
// IsPrimitive returns false.
func (a *Array) IsPrimitive() bool { return false }
// HasAttributes returns true if the array's element type is user defined.
func (a *Array) HasAttributes() bool {
return a.ElemType.Type.HasAttributes()
}
// IsObject returns false.
func (a *Array) IsObject() bool { return false }
// IsArray returns true.
func (a *Array) IsArray() bool { return true }
// IsHash returns false.
func (a *Array) IsHash() bool { return false }
// ToObject returns nil.
func (a *Array) ToObject() Object { return nil }
// ToArray returns a.
func (a *Array) ToArray() *Array { return a }
// ToHash returns nil.
func (a *Array) ToHash() *Hash { return nil }
// CanHaveDefault returns true if the array type can have a default value.
// The array type can have a default value only if the element type can
// have a default value.
func (a *Array) CanHaveDefault() bool {
return a.ElemType.Type.CanHaveDefault()
}
// IsCompatible returns true if val is compatible with p.
func (a *Array) IsCompatible(val interface{}) bool {
k := reflect.TypeOf(val).Kind()
if k != reflect.Array && k != reflect.Slice {
return false
}
v := reflect.ValueOf(val)
for i := 0; i < v.Len(); i++ {
compat := (a.ElemType.Type != nil) && a.ElemType.Type.IsCompatible(v.Index(i).Interface())
if !compat {
return false
}
}
return true
}
// GenerateExample produces a random array value.
func (a *Array) GenerateExample(r *RandomGenerator, seen []string) interface{} {
count := r.Int()%3 + 1
res := make([]interface{}, count)
for i := 0; i < count; i++ {
res[i] = a.ElemType.Type.GenerateExample(r, seen)
}
return a.MakeSlice(res)
}
// MakeSlice examines the key type from the Array and create a slice with builtin type if possible.
// The idea is to avoid generating []interface{} and produce more known types.
func (a *Array) MakeSlice(s []interface{}) interface{} {
slice := reflect.MakeSlice(toReflectType(a), 0, len(s))
for _, item := range s {
slice = reflect.Append(slice, reflect.ValueOf(item))
}
return slice.Interface()
}
// Kind implements DataKind.
func (o Object) Kind() Kind { return ObjectKind }
// Name returns the type name.
func (o Object) Name() string { return "object" }
// IsPrimitive returns false.
func (o Object) IsPrimitive() bool { return false }
// HasAttributes returns true.
func (o Object) HasAttributes() bool { return true }
// IsObject returns true.
func (o Object) IsObject() bool { return true }
// IsArray returns false.
func (o Object) IsArray() bool { return false }
// IsHash returns false.
func (o Object) IsHash() bool { return false }
// ToObject returns the underlying object.
func (o Object) ToObject() Object { return o }
// ToArray returns nil.
func (o Object) ToArray() *Array { return nil }
// ToHash returns nil.
func (o Object) ToHash() *Hash { return nil }
// CanHaveDefault returns false.
func (o Object) CanHaveDefault() bool { return false }
// Merge copies other's attributes into o overridding any pre-existing attribute with the same name.
func (o Object) Merge(other Object) {
for n, att := range other {
o[n] = DupAtt(att)
}
}
// IsCompatible returns true if val is compatible with p.
func (o Object) IsCompatible(val interface{}) bool {
k := reflect.TypeOf(val).Kind()
return k == reflect.Map || k == reflect.Struct
}
// GenerateExample returns a random value of the object.
func (o Object) GenerateExample(r *RandomGenerator, seen []string) interface{} {
// ensure fixed ordering
keys := make([]string, 0, len(o))
for n := range o {
keys = append(keys, n)
}
sort.Strings(keys)
res := make(map[string]interface{})
for _, n := range keys {
att := o[n]
res[n] = att.Type.GenerateExample(r, seen)
}
return res
}
// Kind implements DataKind.
func (h *Hash) Kind() Kind { return HashKind }
// Name returns the type name.
func (h *Hash) Name() string { return "hash" }
// IsPrimitive returns false.
func (h *Hash) IsPrimitive() bool { return false }
// HasAttributes returns true if the either hash's key type is user defined
// or the element type is user defined.
func (h *Hash) HasAttributes() bool {
return h.KeyType.Type.HasAttributes() || h.ElemType.Type.HasAttributes()
}
// IsObject returns false.
func (h *Hash) IsObject() bool { return false }
// IsArray returns false.
func (h *Hash) IsArray() bool { return false }
// IsHash returns true.
func (h *Hash) IsHash() bool { return true }
// ToObject returns nil.
func (h *Hash) ToObject() Object { return nil }
// ToArray returns nil.
func (h *Hash) ToArray() *Array { return nil }
// ToHash returns the underlying hash map.
func (h *Hash) ToHash() *Hash { return h }
// CanHaveDefault returns true if the hash type can have a default value.
// The hash type can have a default value only if both the key type and
// the element type can have a default value.
func (h *Hash) CanHaveDefault() bool {
return h.KeyType.Type.CanHaveDefault() && h.ElemType.Type.CanHaveDefault()
}
// IsCompatible returns true if val is compatible with p.
func (h *Hash) IsCompatible(val interface{}) bool {
k := reflect.TypeOf(val).Kind()
if k != reflect.Map {
return false
}
v := reflect.ValueOf(val)
for _, key := range v.MapKeys() {
keyCompat := h.KeyType.Type == nil || h.KeyType.Type.IsCompatible(key.Interface())
elemCompat := h.ElemType.Type == nil || h.ElemType.Type.IsCompatible(v.MapIndex(key).Interface())
if !keyCompat || !elemCompat {
return false
}
}
return true
}
// GenerateExample returns a random hash value.
func (h *Hash) GenerateExample(r *RandomGenerator, seen []string) interface{} {
count := r.Int()%3 + 1
pair := map[interface{}]interface{}{}
for i := 0; i < count; i++ {
pair[h.KeyType.Type.GenerateExample(r, seen)] = h.ElemType.Type.GenerateExample(r, seen)
}
return h.MakeMap(pair)
}
// MakeMap examines the key type from a Hash and create a map with builtin type if possible.
// The idea is to avoid generating map[interface{}]interface{}, which cannot be handled by json.Marshal.
func (h *Hash) MakeMap(m map[interface{}]interface{}) interface{} {
hash := reflect.MakeMap(toReflectType(h))
for key, value := range m {
hash.SetMapIndex(reflect.ValueOf(key), reflect.ValueOf(value))
}
return hash.Interface()
}
// AttributeIterator is the type of the function given to IterateAttributes.
type AttributeIterator func(string, *AttributeDefinition) error
// IterateAttributes calls the given iterator passing in each attribute sorted in alphabetical order.
// Iteration stops if an iterator returns an error and in this case IterateObject returns that
// error.
func (o Object) IterateAttributes(it AttributeIterator) error {
names := make([]string, len(o))
i := 0
for n := range o {
names[i] = n
i++
}
sort.Strings(names)
for _, n := range names {
if err := it(n, o[n]); err != nil {
return err
}
}
return nil
}
// UserTypes traverses the data type recursively and collects all the user types used to
// define it. The returned map is indexed by type name.
func UserTypes(dt DataType) map[string]*UserTypeDefinition {
collect := func(types map[string]*UserTypeDefinition) func(*AttributeDefinition) error {
return func(at *AttributeDefinition) error {
if u, ok := at.Type.(*UserTypeDefinition); ok {
types[u.TypeName] = u
} else if m, ok := at.Type.(*MediaTypeDefinition); ok {
types[m.TypeName] = m.UserTypeDefinition
}
return nil
}
}
switch actual := dt.(type) {
case Primitive:
return nil
case *Array:
return UserTypes(actual.ElemType.Type)
case *Hash:
ktypes := UserTypes(actual.KeyType.Type)
vtypes := UserTypes(actual.ElemType.Type)
if vtypes == nil {
return ktypes
}
for n, ut := range ktypes {
vtypes[n] = ut
}
return vtypes
case Object:
types := make(map[string]*UserTypeDefinition)
for _, att := range actual {
att.Walk(collect(types))
}
if len(types) == 0 {
return nil
}
return types
case *UserTypeDefinition:
types := map[string]*UserTypeDefinition{actual.TypeName: actual}
actual.Walk(collect(types))
return types
case *MediaTypeDefinition:
types := map[string]*UserTypeDefinition{actual.TypeName: actual.UserTypeDefinition}
actual.Walk(collect(types))
return types
default:
panic("unknown type") // bug
}
}
// ToSlice converts an ArrayVal to a slice.
func (a ArrayVal) ToSlice() []interface{} {
arr := make([]interface{}, len(a))
for i, elem := range a {
switch actual := elem.(type) {
case ArrayVal:
arr[i] = actual.ToSlice()
case HashVal:
arr[i] = actual.ToMap()
default:
arr[i] = actual
}
}
return arr
}
// ToMap converts a HashVal to a map.
func (h HashVal) ToMap() map[interface{}]interface{} {
mp := make(map[interface{}]interface{}, len(h))
for k, v := range h {
switch actual := v.(type) {
case ArrayVal:
mp[k] = actual.ToSlice()
case HashVal:
mp[k] = actual.ToMap()
default:
mp[k] = actual
}
}
return mp
}
// NewUserTypeDefinition creates a user type definition but does not
// execute the DSL.
func NewUserTypeDefinition(name string, dsl func()) *UserTypeDefinition {
return &UserTypeDefinition{
TypeName: name,
AttributeDefinition: &AttributeDefinition{DSLFunc: dsl},
}
}
// Kind implements DataKind.
func (u *UserTypeDefinition) Kind() Kind { return UserTypeKind }
// Name returns the JSON type name.
func (u *UserTypeDefinition) Name() string { return u.Type.Name() }
// IsPrimitive calls IsPrimitive on the user type underlying data type.
func (u *UserTypeDefinition) IsPrimitive() bool { return u.Type != nil && u.Type.IsPrimitive() }
// HasAttributes calls the HasAttributes on the user type underlying data type.
func (u *UserTypeDefinition) HasAttributes() bool { return u.Type.HasAttributes() }
// IsObject calls IsObject on the user type underlying data type.
func (u *UserTypeDefinition) IsObject() bool { return u.Type != nil && u.Type.IsObject() }
// IsArray calls IsArray on the user type underlying data type.
func (u *UserTypeDefinition) IsArray() bool { return u.Type != nil && u.Type.IsArray() }
// IsHash calls IsHash on the user type underlying data type.
func (u *UserTypeDefinition) IsHash() bool { return u.Type != nil && u.Type.IsHash() }
// ToObject calls ToObject on the user type underlying data type.
func (u *UserTypeDefinition) ToObject() Object { return u.Type.ToObject() }
// ToArray calls ToArray on the user type underlying data type.
func (u *UserTypeDefinition) ToArray() *Array { return u.Type.ToArray() }
// ToHash calls ToHash on the user type underlying data type.
func (u *UserTypeDefinition) ToHash() *Hash { return u.Type.ToHash() }
// CanHaveDefault calls CanHaveDefault on the user type underlying data type.
func (u *UserTypeDefinition) CanHaveDefault() bool { return u.Type.CanHaveDefault() }
// IsCompatible returns true if val is compatible with u.
func (u *UserTypeDefinition) IsCompatible(val interface{}) bool {
return u.Type == nil || u.Type.IsCompatible(val)
}
// Finalize merges base type attributes.
func (u *UserTypeDefinition) Finalize() {
if u.Reference != nil {
if bat := u.AttributeDefinition; bat != nil {
u.AttributeDefinition.Inherit(bat)
}
}
u.GenerateExample(Design.RandomGenerator(), nil)
}
// NewMediaTypeDefinition creates a media type definition but does not
// execute the DSL.
func NewMediaTypeDefinition(name, identifier string, dsl func()) *MediaTypeDefinition {
return &MediaTypeDefinition{
UserTypeDefinition: &UserTypeDefinition{
AttributeDefinition: &AttributeDefinition{Type: Object{}, DSLFunc: dsl},
TypeName: name,
},
Identifier: identifier,
}
}
// Kind implements DataKind.
func (m *MediaTypeDefinition) Kind() Kind { return MediaTypeKind }
// IsError returns true if the media type is implemented via a goa struct.
func (m *MediaTypeDefinition) IsError() bool {
base, params, err := mime.ParseMediaType(m.Identifier)
if err != nil {
panic("invalid media type identifier " + m.Identifier) // bug
}
delete(params, "view")
return mime.FormatMediaType(base, params) == ErrorMedia.Identifier
}
// ComputeViews returns the media type views recursing as necessary if the media type is a
// collection.
func (m *MediaTypeDefinition) ComputeViews() map[string]*ViewDefinition {
if m.Views != nil {
return m.Views
}
if m.IsArray() {
if mt, ok := m.ToArray().ElemType.Type.(*MediaTypeDefinition); ok {
return mt.ComputeViews()
}
}
return nil
}
// Finalize sets the value of ContentType to the identifier if not set.
func (m *MediaTypeDefinition) Finalize() {
if m.ContentType == "" {
m.ContentType = m.Identifier
}
m.UserTypeDefinition.Finalize()
}
// ViewIterator is the type of the function given to IterateViews.
type ViewIterator func(*ViewDefinition) error
// IterateViews calls the given iterator passing in each attribute sorted in alphabetical order.
// Iteration stops if an iterator returns an error and in this case IterateViews returns that
// error.
func (m *MediaTypeDefinition) IterateViews(it ViewIterator) error {
o := m.Views
// gather names and sort them
names := make([]string, len(o))
i := 0
for n := range o {
names[i] = n
i++
}
sort.Strings(names)
// iterate
for _, n := range names {
if err := it(o[n]); err != nil {
return err
}
}
return nil
}
// Project creates a MediaTypeDefinition containing the fields defined in the given view. The
// resuling media type only defines the default view and its identifier is modified to indicate that
// it was projected by adding the view as id parameter. links is a user type of type Object where
// each key corresponds to a linked media type as defined by the media type "links" attribute.
func (m *MediaTypeDefinition) Project(view string) (*MediaTypeDefinition, *UserTypeDefinition, error) {
canonical := m.projectCanonical(view)
if p, ok := ProjectedMediaTypes[canonical]; ok {
var links *UserTypeDefinition
mLinks := ProjectedMediaTypes[canonical+"; links"]
if mLinks != nil {
links = mLinks.UserTypeDefinition
}
return p, links, nil
}
if m.IsArray() {
return m.projectCollection(view)
}
return m.projectSingle(view, canonical)
}
func (m *MediaTypeDefinition) projectSingle(view, canonical string) (p *MediaTypeDefinition, links *UserTypeDefinition, err error) {
v, ok := m.Views[view]
if !ok {
return nil, nil, fmt.Errorf("unknown view %#v", view)
}
viewObj := v.Type.ToObject()
// Compute validations - view may not have all attributes
var val *dslengine.ValidationDefinition
if m.Validation != nil {
names := m.Validation.Required
var required []string
for _, n := range names {
if _, ok := viewObj[n]; ok {
required = append(required, n)
}
}
val = m.Validation.Dup()
val.Required = required
}
// Compute description
desc := m.Description
if desc == "" {
desc = m.TypeName + " media type"
}
desc += " (" + view + " view)"
p = &MediaTypeDefinition{
Identifier: m.projectIdentifier(view),
UserTypeDefinition: &UserTypeDefinition{
TypeName: m.projectTypeName(view),
AttributeDefinition: &AttributeDefinition{
Description: desc,
Type: Dup(v.Type),
Validation: val,
},
},
}
p.Views = map[string]*ViewDefinition{"default": {
Name: "default",
AttributeDefinition: DupAtt(v.AttributeDefinition),
Parent: p,
}}
ProjectedMediaTypes[canonical] = p
projectedObj := p.Type.ToObject()
mtObj := m.Type.ToObject()
_, hasAttNamedLinks := mtObj["links"]
for n := range viewObj {
if n == "links" && !hasAttNamedLinks {
linkObj := make(Object)
for n, link := range m.Links {
linkView := link.View
if linkView == "" {
linkView = "link"
}
mtAtt, ok := mtObj[n]
if !ok {
return nil, nil, fmt.Errorf("unknown attribute %#v used in links", n)
}
mtt := mtAtt.Type.(*MediaTypeDefinition)
vl, _, err := mtt.Project(linkView)
if err != nil {
return nil, nil, err
}
linkObj[n] = &AttributeDefinition{Type: vl, Validation: mtt.Validation, Metadata: mtAtt.Metadata}
}
lTypeName := fmt.Sprintf("%sLinks", m.TypeName)
links = &UserTypeDefinition{
AttributeDefinition: &AttributeDefinition{
Description: fmt.Sprintf("%s contains links to related resources of %s.", lTypeName, m.TypeName),
Type: linkObj,
},
TypeName: lTypeName,
}
projectedObj[n] = &AttributeDefinition{Type: links, Description: "Links to related resources"}
ProjectedMediaTypes[canonical+"; links"] = &MediaTypeDefinition{UserTypeDefinition: links}
} else {
if at := mtObj[n]; at != nil {
at = DupAtt(at)
if mt, ok := at.Type.(*MediaTypeDefinition); ok {
vatt := viewObj[n]
view := vatt.View
if view == "" {
view = at.View
}
if view == "" {
view = DefaultView
}
pr, _, err := mt.Project(view)
if err != nil {
return nil, nil, fmt.Errorf("view %#v on field %#v cannot be computed: %s", view, n, err)
}
at.Type = pr
// Force example to be generated again
// since set of attributes has changed
at.Example = nil
}
projectedObj[n] = at
}
}
}
return
}
func (m *MediaTypeDefinition) projectCollection(view string) (*MediaTypeDefinition, *UserTypeDefinition, error) {
// Project the collection element media type
e := m.ToArray().ElemType.Type.(*MediaTypeDefinition) // validation checked this cast would work
pe, le, err2 := e.Project(view)
if err2 != nil {
return nil, nil, fmt.Errorf("collection element: %s", err2)
}
// Build the projected collection with the results
desc := m.TypeName + " is the media type for an array of " + e.TypeName + " (" + view + " view)"
p := &MediaTypeDefinition{
Identifier: m.projectIdentifier(view),
UserTypeDefinition: &UserTypeDefinition{
AttributeDefinition: &AttributeDefinition{
Description: desc,
Type: &Array{ElemType: &AttributeDefinition{Type: pe}},
Example: nil,
},
TypeName: pe.TypeName + "Collection",
},
}
p.Views = map[string]*ViewDefinition{"default": &ViewDefinition{
AttributeDefinition: DupAtt(pe.Views["default"].AttributeDefinition),
Name: "default",
Parent: p,
}}
// Run the DSL that was created by the CollectionOf function
if !dslengine.Execute(p.DSL(), p) {
return nil, nil, dslengine.Errors
}
// Build the links user type
var links *UserTypeDefinition
if le != nil {
lTypeName := le.TypeName + "Array"
links = &UserTypeDefinition{
AttributeDefinition: &AttributeDefinition{
Type: &Array{ElemType: &AttributeDefinition{Type: le}},
Description: fmt.Sprintf("%s contains links to related resources of %s.", lTypeName, m.TypeName),
},
TypeName: lTypeName,
}
}
return p, links, nil
}
// projectIdentifier computes the projected media type identifier by adding the "view" param. We
// need the projected media type identifier to be different so that looking up projected media types
// from ProjectedMediaTypes works correctly. It's also good for clients.
func (m *MediaTypeDefinition) projectIdentifier(view string) string {
base, params, err := mime.ParseMediaType(m.Identifier)
if err != nil {
base = m.Identifier
}
params["view"] = view
return mime.FormatMediaType(base, params)
}
// projectIdentifier computes the projected canonical media type identifier by adding the "view"
// param if the view is not the default view.
func (m *MediaTypeDefinition) projectCanonical(view string) string {
cano := CanonicalIdentifier(m.Identifier)
base, params, _ := mime.ParseMediaType(cano)
if params["view"] != "" {
return cano // Already projected
}
params["view"] = view
return mime.FormatMediaType(base, params)
}
// projectTypeName appends the view name to the media type name if the view name is not "default".
func (m *MediaTypeDefinition) projectTypeName(view string) string {
typeName := m.TypeName
if view != "default" {
typeName += strings.Title(view)
}
return typeName
}
// DataStructure implementation
// Definition returns the underlying attribute definition.
// Note that this function is "inherited" by both UserTypeDefinition and
// MediaTypeDefinition.
func (a *AttributeDefinition) Definition() *AttributeDefinition {
return a
}
// Walk traverses the data structure recursively and calls the given function once
// on each attribute starting with the attribute returned by Definition.
func (a *AttributeDefinition) Walk(walker func(*AttributeDefinition) error) error {
return walk(a, walker, make(map[string]bool))
}
// Walk traverses the data structure recursively and calls the given function once
// on each attribute starting with the attribute returned by Definition.
func (u *UserTypeDefinition) Walk(walker func(*AttributeDefinition) error) error {
return walk(u.AttributeDefinition, walker, map[string]bool{u.TypeName: true})
}
// Recursive implementation of the Walk methods. Takes care of avoiding infinite recursions by
// keeping track of types that have already been walked.
func walk(at *AttributeDefinition, walker func(*AttributeDefinition) error, seen map[string]bool) error {
if err := walker(at); err != nil {
return err
}
walkUt := func(ut *UserTypeDefinition) error {
if _, ok := seen[ut.TypeName]; ok {
return nil
}
seen[ut.TypeName] = true
return walk(ut.AttributeDefinition, walker, seen)
}
switch actual := at.Type.(type) {
case Primitive:
return nil
case *Array: