Documentation

Overview

    Package bson is an implementation of the BSON specification for Go:

    http://bsonspec.org
    

    It was created as part of the mgo MongoDB driver for Go, but is standalone and may be used on its own without the driver.

    Index

    Constants

    This section is empty.

    Variables

    View Source
    var MaxKey = orderKey(1<<63 - 1)

      MaxKey is a special value that compares higher than all other possible BSON values in a MongoDB database.

      View Source
      var MinKey = orderKey(-1 << 63)

        MinKey is a special value that compares lower than all other possible BSON values in a MongoDB database.

        View Source
        var SetZero = errors.New("set to zero")

          SetZero may be returned from a SetBSON method to have the value set to its respective zero value. When used in pointer values, this will set the field to nil rather than to the pre-allocated value.

          View Source
          var Undefined undefined

            Undefined represents the undefined BSON value.

            Functions

            func IsObjectIdHex

            func IsObjectIdHex(s string) bool

              IsObjectIdHex returns whether s is a valid hex representation of an ObjectId. See the ObjectIdHex function.

              func Marshal

              func Marshal(in interface{}) (out []byte, err error)

                Marshal serializes the in value, which may be a map or a struct value. In the case of struct values, only exported fields will be serialized. The lowercased field name is used as the key for each exported field, but this behavior may be changed using the respective field tag. The tag may also contain flags to tweak the marshalling behavior for the field. The tag formats accepted are:

                "[<key>][,<flag1>[,<flag2>]]"
                
                `(...) bson:"[<key>][,<flag1>[,<flag2>]]" (...)`
                

                The following flags are currently supported:

                omitempty  Only include the field if it's not set to the zero
                           value for the type or to empty slices or maps.
                
                minsize    Marshal an int64 value as an int32, if that's feasible
                           while preserving the numeric value.
                
                inline     Inline the field, which must be a struct or a map,
                           causing all of its fields or keys to be processed as if
                           they were part of the outer struct. For maps, keys must
                           not conflict with the bson keys of other struct fields.
                

                Some examples:

                type T struct {
                    A bool
                    B int    "myb"
                    C string "myc,omitempty"
                    D string `bson:",omitempty" json:"jsonkey"`
                    E int64  ",minsize"
                    F int64  "myf,omitempty,minsize"
                }
                

                func Now

                func Now() time.Time

                  Now returns the current time with millisecond precision. MongoDB stores timestamps with the same precision, so a Time returned from this method will not change after a roundtrip to the database. That's the only reason why this function exists. Using the time.Now function also works fine otherwise.

                  func Unmarshal

                  func Unmarshal(in []byte, out interface{}) (err error)

                    Unmarshal deserializes data from in into the out value. The out value must be a map, a pointer to a struct, or a pointer to a bson.D value. The lowercased field name is used as the key for each exported field, but this behavior may be changed using the respective field tag. The tag may also contain flags to tweak the marshalling behavior for the field. The tag formats accepted are:

                    "[<key>][,<flag1>[,<flag2>]]"
                    
                    `(...) bson:"[<key>][,<flag1>[,<flag2>]]" (...)`
                    

                    The following flags are currently supported during unmarshal (see the Marshal method for other flags):

                    inline     Inline the field, which must be a struct or a map.
                               Inlined structs are handled as if its fields were part
                               of the outer struct. An inlined map causes keys that do
                               not match any other struct field to be inserted in the
                               map rather than being discarded as usual.
                    

                    The target field or element types of out may not necessarily match the BSON values of the provided data. The following conversions are made automatically:

                    - Numeric types are converted if at least the integer part of the

                    value would be preserved correctly
                    

                    - Bools are converted to numeric types as 1 or 0 - Numeric types are converted to bools as true if not 0 or false otherwise - Binary and string BSON data is converted to a string, array or byte slice

                    If the value would not fit the type and cannot be converted, it's silently skipped.

                    Pointer values are initialized when necessary.

                    Types

                    type Binary

                    type Binary struct {
                    	Kind byte
                    	Data []byte
                    }

                      Binary is a representation for non-standard binary values. Any kind should work, but the following are known as of this writing:

                      0x00 - Generic. This is decoded as []byte(data), not Binary{0x00, data}.
                      0x01 - Function (!?)
                      0x02 - Obsolete generic.
                      0x03 - UUID
                      0x05 - MD5
                      0x80 - User defined.
                      

                      type D

                      type D []DocElem

                        D represents a BSON document containing ordered elements. For example:

                        bson.D{{"a", 1}, {"b", true}}
                        

                        In some situations, such as when creating indexes for MongoDB, the order in which the elements are defined is important. If the order is not important, using a map is generally more comfortable. See bson.M and bson.RawD.

                        func (D) Map

                        func (d D) Map() (m M)

                          Map returns a map out of the ordered element name/value pairs in d.

                          type DocElem

                          type DocElem struct {
                          	Name  string
                          	Value interface{}
                          }

                            See the D type.

                            type Getter

                            type Getter interface {
                            	GetBSON() (interface{}, error)
                            }

                              A value implementing the bson.Getter interface will have its GetBSON method called when the given value has to be marshalled, and the result of this method will be marshaled in place of the actual object.

                              If GetBSON returns return a non-nil error, the marshalling procedure will stop and error out with the provided value.

                              type JavaScript

                              type JavaScript struct {
                              	Code  string
                              	Scope interface{}
                              }

                                JavaScript is a type that holds JavaScript code. If Scope is non-nil, it will be marshaled as a mapping from identifiers to values that may be used when evaluating the provided Code.

                                type M

                                type M map[string]interface{}

                                  M is a convenient alias for a map[string]interface{} map, useful for dealing with BSON in a native way. For instance:

                                  bson.M{"a": 1, "b": true}
                                  

                                  There's no special handling for this type in addition to what's done anyway for an equivalent map type. Elements in the map will be dumped in an undefined ordered. See also the bson.D type for an ordered alternative.

                                  type MongoTimestamp

                                  type MongoTimestamp int64

                                    MongoTimestamp is a special internal type used by MongoDB that for some strange reason has its own datatype defined in BSON.

                                    type ObjectId

                                    type ObjectId string

                                      ObjectId is a unique ID identifying a BSON value. It must be exactly 12 bytes long. MongoDB objects by default have such a property set in their "_id" property.

                                      http://www.mongodb.org/display/DOCS/Object+IDs

                                      func NewObjectId

                                      func NewObjectId() ObjectId

                                        NewObjectId returns a new unique ObjectId.

                                        func NewObjectIdWithTime

                                        func NewObjectIdWithTime(t time.Time) ObjectId

                                          NewObjectIdWithTime returns a dummy ObjectId with the timestamp part filled with the provided number of seconds from epoch UTC, and all other parts filled with zeroes. It's not safe to insert a document with an id generated by this method, it is useful only for queries to find documents with ids generated before or after the specified timestamp.

                                          func ObjectIdHex

                                          func ObjectIdHex(s string) ObjectId

                                            ObjectIdHex returns an ObjectId from the provided hex representation. Calling this function with an invalid hex representation will cause a runtime panic. See the IsObjectIdHex function.

                                            func (ObjectId) Counter

                                            func (id ObjectId) Counter() int32

                                              Counter returns the incrementing value part of the id. It's a runtime error to call this method with an invalid id.

                                              func (ObjectId) Hex

                                              func (id ObjectId) Hex() string

                                                Hex returns a hex representation of the ObjectId.

                                                func (ObjectId) Machine

                                                func (id ObjectId) Machine() []byte

                                                  Machine returns the 3-byte machine id part of the id. It's a runtime error to call this method with an invalid id.

                                                  func (ObjectId) MarshalJSON

                                                  func (id ObjectId) MarshalJSON() ([]byte, error)

                                                    MarshalJSON turns a bson.ObjectId into a json.Marshaller.

                                                    func (ObjectId) Pid

                                                    func (id ObjectId) Pid() uint16

                                                      Pid returns the process id part of the id. It's a runtime error to call this method with an invalid id.

                                                      func (ObjectId) String

                                                      func (id ObjectId) String() string

                                                        String returns a hex string representation of the id. Example: ObjectIdHex("4d88e15b60f486e428412dc9").

                                                        func (ObjectId) Time

                                                        func (id ObjectId) Time() time.Time

                                                          Time returns the timestamp part of the id. It's a runtime error to call this method with an invalid id.

                                                          func (*ObjectId) UnmarshalJSON

                                                          func (id *ObjectId) UnmarshalJSON(data []byte) error

                                                            UnmarshalJSON turns *bson.ObjectId into a json.Unmarshaller.

                                                            func (ObjectId) Valid

                                                            func (id ObjectId) Valid() bool

                                                              Valid returns true if id is valid. A valid id must contain exactly 12 bytes.

                                                              type Raw

                                                              type Raw struct {
                                                              	Kind byte
                                                              	Data []byte
                                                              }

                                                                The Raw type represents raw unprocessed BSON documents and elements. Kind is the kind of element as defined per the BSON specification, and Data is the raw unprocessed data for the respective element. Using this type it is possible to unmarshal or marshal values partially.

                                                                Relevant documentation:

                                                                http://bsonspec.org/#/specification
                                                                

                                                                func (Raw) Unmarshal

                                                                func (raw Raw) Unmarshal(out interface{}) (err error)

                                                                  Unmarshal deserializes raw into the out value. If the out value type is not compatible with raw, a *bson.TypeError is returned.

                                                                  See the Unmarshal function documentation for more details on the unmarshalling process.

                                                                  type RawD

                                                                  type RawD []RawDocElem

                                                                    RawD represents a BSON document containing raw unprocessed elements. This low-level representation may be useful when lazily processing documents of uncertain content, or when manipulating the raw content documents in general.

                                                                    type RawDocElem

                                                                    type RawDocElem struct {
                                                                    	Name  string
                                                                    	Value Raw
                                                                    }

                                                                      See the RawD type.

                                                                      type RegEx

                                                                      type RegEx struct {
                                                                      	Pattern string
                                                                      	Options string
                                                                      }

                                                                        RegEx represents a regular expression. The Options field may contain individual characters defining the way in which the pattern should be applied, and must be sorted. Valid options as of this writing are 'i' for case insensitive matching, 'm' for multi-line matching, 'x' for verbose mode, 'l' to make \w, \W, and similar be locale-dependent, 's' for dot-all mode (a '.' matches everything), and 'u' to make \w, \W, and similar match unicode. The value of the Options parameter is not verified before being marshaled into the BSON format.

                                                                        type Setter

                                                                        type Setter interface {
                                                                        	SetBSON(raw Raw) error
                                                                        }

                                                                          A value implementing the bson.Setter interface will receive the BSON value via the SetBSON method during unmarshaling, and the object itself will not be changed as usual.

                                                                          If setting the value works, the method should return nil or alternatively bson.SetZero to set the respective field to its zero value (nil for pointer types). If SetBSON returns a value of type bson.TypeError, the BSON value will be omitted from a map or slice being decoded and the unmarshalling will continue. If it returns any other non-nil error, the unmarshalling procedure will stop and error out with the provided value.

                                                                          This interface is generally useful in pointer receivers, since the method will want to change the receiver. A type field that implements the Setter interface doesn't have to be a pointer, though.

                                                                          Unlike the usual behavior, unmarshalling onto a value that implements a Setter interface will NOT reset the value to its zero state. This allows the value to decide by itself how to be unmarshalled.

                                                                          For example:

                                                                          type MyString string
                                                                          
                                                                          func (s *MyString) SetBSON(raw bson.Raw) error {
                                                                              return raw.Unmarshal(s)
                                                                          }
                                                                          

                                                                          type Symbol

                                                                          type Symbol string

                                                                            The Symbol type is similar to a string and is used in languages with a distinct symbol type.

                                                                            type TypeError

                                                                            type TypeError struct {
                                                                            	Type reflect.Type
                                                                            	Kind byte
                                                                            }

                                                                            func (*TypeError) Error

                                                                            func (e *TypeError) Error() string