github.com/mayra-cabrera/buffalo@v0.9.4-0.20170814145312-66d2e7772f11/binding/binding.go (about)

     1  package binding
     2  
     3  import (
     4  	"encoding/json"
     5  	"encoding/xml"
     6  	"net/http"
     7  	"strings"
     8  	"sync"
     9  	"time"
    10  
    11  	"github.com/markbates/pop/nulls"
    12  	"github.com/monoculum/formam"
    13  	"github.com/pkg/errors"
    14  )
    15  
    16  // Binder takes a request and binds it to an interface.
    17  // If there is a problem it should return an error.
    18  type Binder func(*http.Request, interface{}) error
    19  
    20  // CustomTypeDecoder converts a custom type from the request insto its exact type.
    21  type CustomTypeDecoder func([]string) (interface{}, error)
    22  
    23  // binders is a map of the defined content-type related binders.
    24  var binders = map[string]Binder{}
    25  
    26  var decoder *formam.Decoder
    27  var lock = &sync.Mutex{}
    28  var timeFormats = []string{
    29  	"2006-01-02T15:04:05Z07:00",
    30  	"01/02/2006",
    31  	"2006-01-02",
    32  	time.ANSIC,
    33  	time.UnixDate,
    34  	time.RubyDate,
    35  	time.RFC822,
    36  	time.RFC822Z,
    37  	time.RFC850,
    38  	time.RFC1123,
    39  	time.RFC1123Z,
    40  	time.RFC3339,
    41  	time.RFC3339Nano,
    42  	time.Kitchen,
    43  	time.Stamp,
    44  	time.StampMilli,
    45  	time.StampMicro,
    46  	time.StampNano,
    47  }
    48  
    49  // RegisterTimeFormats allows to add custom time layouts that
    50  // the binder will be able to use for decoding.
    51  func RegisterTimeFormats(layouts ...string) {
    52  	timeFormats = append(timeFormats, layouts...)
    53  }
    54  
    55  // RegisterCustomDecorder allows to define custom type decoders.
    56  func RegisterCustomDecorder(fn CustomTypeDecoder, types []interface{}, fields []interface{}) {
    57  	rawFunc := (func([]string) (interface{}, error))(fn)
    58  	decoder.RegisterCustomType(rawFunc, types, fields)
    59  }
    60  
    61  // Register maps a request Content-Type (application/json)
    62  // to a Binder.
    63  func Register(contentType string, fn Binder) {
    64  	lock.Lock()
    65  	defer lock.Unlock()
    66  
    67  	binders[strings.ToLower(contentType)] = fn
    68  }
    69  
    70  // Exec will bind the interface to the request.Body. The type of binding
    71  // is dependent on the "Content-Type" for the request. If the type
    72  // is "application/json" it will use "json.NewDecoder". If the type
    73  // is "application/xml" it will use "xml.NewDecoder". The default
    74  // binder is "https://github.com/monoculum/formam".
    75  func Exec(req *http.Request, value interface{}) error {
    76  	ct := strings.ToLower(req.Header.Get("Content-Type"))
    77  	if ct != "" {
    78  		cts := strings.Split(ct, ";")
    79  		c := cts[0]
    80  		if b, ok := binders[strings.TrimSpace(c)]; ok {
    81  			return b(req, value)
    82  		}
    83  		return errors.Errorf("could not find a binder for %s", c)
    84  	}
    85  	return errors.New("blank content type")
    86  }
    87  
    88  func init() {
    89  	decoder = formam.NewDecoder(&formam.DecoderOptions{
    90  		TagName:           "form",
    91  		IgnoreUnknownKeys: true,
    92  	})
    93  
    94  	decoder.RegisterCustomType(func(vals []string) (interface{}, error) {
    95  		return parseTime(vals)
    96  	}, []interface{}{time.Time{}}, nil)
    97  
    98  	decoder.RegisterCustomType(func(vals []string) (interface{}, error) {
    99  		var ti nulls.Time
   100  
   101  		t, err := parseTime(vals)
   102  		if err != nil {
   103  			return ti, errors.WithStack(err)
   104  		}
   105  		ti.Time = t
   106  		ti.Valid = true
   107  
   108  		return ti, nil
   109  	}, []interface{}{nulls.Time{}}, nil)
   110  
   111  	sb := func(req *http.Request, i interface{}) error {
   112  		err := req.ParseForm()
   113  		if err != nil {
   114  			return errors.WithStack(err)
   115  		}
   116  
   117  		if err := decoder.Decode(req.Form, i); err != nil {
   118  			return errors.WithStack(err)
   119  		}
   120  		return nil
   121  	}
   122  
   123  	binders["application/html"] = sb
   124  	binders["text/html"] = sb
   125  	binders["application/x-www-form-urlencoded"] = sb
   126  	binders["multipart/form-data"] = sb
   127  	binders["html"] = sb
   128  }
   129  
   130  func init() {
   131  	jb := func(req *http.Request, value interface{}) error {
   132  		return json.NewDecoder(req.Body).Decode(value)
   133  	}
   134  
   135  	binders["application/json"] = jb
   136  	binders["text/json"] = jb
   137  	binders["json"] = jb
   138  }
   139  
   140  func init() {
   141  	xb := func(req *http.Request, value interface{}) error {
   142  		return xml.NewDecoder(req.Body).Decode(value)
   143  	}
   144  
   145  	binders["application/xml"] = xb
   146  	binders["text/xml"] = xb
   147  	binders["xml"] = xb
   148  }
   149  
   150  func parseTime(vals []string) (time.Time, error) {
   151  	var t time.Time
   152  	var err error
   153  
   154  	// don't try to parse empty time values, it will raise an error
   155  	if len(vals) == 0 || vals[0] == "" {
   156  		return t, nil
   157  	}
   158  
   159  	for _, layout := range timeFormats {
   160  		t, err = time.Parse(layout, vals[0])
   161  		if err == nil {
   162  			return t, nil
   163  		}
   164  	}
   165  
   166  	if err != nil {
   167  		return t, errors.WithStack(err)
   168  	}
   169  
   170  	return t, nil
   171  }