/
middlewares.go
91 lines (81 loc) · 2.42 KB
/
middlewares.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
package middlewares
import "fmt"
// Registry - Middlewares registry.
type Registry struct {
middlewares map[string]*middleware
}
// New - Constructs new middlewares registry.
func New() *Registry {
return &Registry{
middlewares: make(map[string]*middleware),
}
}
// middleware - Middleware stored in registry with additional defaults.
type middleware struct {
Descriptor
Constructor
Defaults *Middleware
}
// Register - Registers a middleware constructor function.
// Panics if descriptor name is empty.
func (registry *Registry) Register(desc Descriptor, constructor Constructor) {
if desc.Name == "" {
panic("middleware name cannot be empty")
}
for _, opt := range desc.Options {
if opt.Type == "" {
panic(fmt.Sprintf("Middlewares %q: option %q type cannot be empty", desc.Name, opt.Name))
}
}
registry.middlewares[desc.Name] = &middleware{
Descriptor: desc,
Constructor: constructor,
}
}
// Alias - Registers a middleware alias with overwritten options defaults.
func (registry *Registry) Alias(source, dest string, def *Middleware) {
registry.middlewares[dest] = &middleware{
Defaults: def,
Descriptor: registry.middlewares[source].Descriptor,
Constructor: registry.middlewares[source].Constructor,
}
registry.middlewares[dest].Descriptor.Name = dest
}
// Construct - Constructs middleware handler from name and options.
func (registry *Registry) Construct(m *Middleware) (Handler, error) {
md, ok := registry.middlewares[m.Name]
if !ok {
return nil, fmt.Errorf("middleware %q doesn't exist", m.Name)
}
if md.Defaults != nil {
m.SetDefaults(md.Defaults)
}
if err := m.Validate(md.Descriptor.Options); err != nil {
return nil, fmt.Errorf("In middleware %q: %v", md.Descriptor.Name, err)
}
opts, err := m.ConstructOptions()
if err != nil {
return nil, err
}
return md.Constructor(opts)
}
// Exists - Checks if middleware with given name exists in registry.
func (registry *Registry) Exists(name string) bool {
_, ok := registry.middlewares[name]
return ok
}
// Descriptors - Returns all registered middlewares descriptors.
func (registry *Registry) Descriptors() (desc []Descriptor) {
for _, v := range registry.middlewares {
desc = append(desc, v.Descriptor)
}
return
}
// DescriptorByName - Returns middleware descriptor by name.
func (registry *Registry) DescriptorByName(name string) (_ Descriptor, _ bool) {
md, ok := registry.middlewares[name]
if !ok {
return
}
return md.Descriptor, true
}