func Inject(value reflect.Value, tagValue string) (bool, error) {
if typeOfFile.AssignableTo(value.Type()) || typeOfFile.ConvertibleTo(value.Type()) {
file, err := os.Open(tagValue)
if err != nil {
return false, err
}
fmt.Printf("%s\n", value)
value.Elem().Set(reflect.ValueOf(file).Elem())
return true, nil
} else {
tag, optionalType := tags.ParseTag(tagValue)
file, err := os.Open(tag)
if err != nil {
return false, err
}
fileType := string(optionalType)
if fileType == "" {
fileType = filepath.Ext(tag)[1:]
}
if fileType == "" {
return false, fmt.Errorf("no extension or type option given for file: %s", tag)
}
switch fileType {
case "txt":
if bytes, err := ioutil.ReadAll(file); err != nil {
return false, err
} else {
value.SetString(string(bytes))
}
case "json":
if err := json.NewDecoder(file).Decode(value.Interface()); err != nil {
return false, err
}
case "xml":
if err := xml.NewDecoder(file).Decode(value.Interface()); err != nil {
return false, err
}
case "gob":
if err := gob.NewDecoder(file).Decode(value.Interface()); err != nil {
return false, err
}
default:
return false, fmt.Errorf("unable to read file %s, unrecognized file type %s", tag, fileType)
}
return true, nil
}
}
// Binds modules. Calls Provide() on modules implementing Provider, calls inject.Injectors for tagged fields, and
// injects provided fields.
func (binder *Binder) Bind(modules ...interface{}) error {
binding := newBinding(binder)
// Holds errors during binding.
errs := make([]error, 0)
// Validate configuration
if _, ok := binding.injectors["provide"]; ok {
return errors.New("the 'provide' tag key may not be overridden")
}
if _, ok := binding.injectors["inject"]; ok {
return errors.New("the 'inject' tag key may not be overridden")
}
// Collect errors in a goroutine.
go func() {
for err := range binding.errors {
errs = append(errs, err)
}
}()
// Injection goroutines signal here when complete.
var injections sync.WaitGroup
// Bind each module.
for _, module := range modules {
// If this module is a Provider then call Provide().
if provider, ok := module.(Provider); ok {
if err := provider.Provide(); err != nil {
return &AnnotatedError{msg: "error during call to Provide()", cause: err}
}
}
// Bind each field in this module.
moduleType := reflect.TypeOf(module).Elem()
for i := 0; i < moduleType.NumField(); i++ {
field := moduleType.Field(i)
value := reflect.ValueOf(module).Elem().Field(i)
tag := tags.StructTag(string(field.Tag))
if bindName, ok := tag.Get("inject"); ok {
if !value.CanSet() {
binding.errors <- fmt.Errorf("cannot inject unexported field: %s", field.Name)
continue
}
injections.Add(1)
go func() {
// Blocks until a provider binds key, or cancelled.
binding.inject(bindName, value)
injections.Done()
}()
} else if tagValue, ok := tag.Get("provide"); ok {
bindName, options := tags.ParseTag(tagValue)
// Releases blocking injections for key.
if err := binding.provide(bindName, options.Contains("singleton"), tag, value); err != nil {
binding.errors <- err
}
}
}
}
// Wait for all injection goroutines to complete.
injections.Wait()
// Signal error processing goroutine to complete.
close(binding.errors)
if len(errs) > 0 {
return &BindingError{errs}
}
return nil
}