The len prefix is superficial and causes the invalid utf-8 error:
package main
import (
"encoding/base64"
"fmt"
"log"
)
func main() {
str := base64.StdEncoding.EncodeToString([]byte("Hello, playground"))
fmt.Println(str)
data, err := base64.StdEncoding.DecodeString(str)
if err != nil {
log.Fatal("error:", err)
}
fmt.Printf("%q\n", data)
}
(Also here)
Output
SGVsbG8sIHBsYXlncm91bmQ=
"Hello, playground"
EDIT: I read too fast, the len was not used as a prefix. dystroy got it right.
Answer from zzzz on Stack OverflowGo by Example
gobyexample.com โบ base64-encoding
Go by Example: Base64 Encoding
Go provides built-in support for base64 encoding/decoding ยท This syntax imports the encoding/base64 package with the b64 name instead of the default base64. Itโll save us some space below
Top answer 1 of 5
69
The len prefix is superficial and causes the invalid utf-8 error:
package main
import (
"encoding/base64"
"fmt"
"log"
)
func main() {
str := base64.StdEncoding.EncodeToString([]byte("Hello, playground"))
fmt.Println(str)
data, err := base64.StdEncoding.DecodeString(str)
if err != nil {
log.Fatal("error:", err)
}
fmt.Printf("%q\n", data)
}
(Also here)
Output
SGVsbG8sIHBsYXlncm91bmQ=
"Hello, playground"
EDIT: I read too fast, the len was not used as a prefix. dystroy got it right.
2 of 5
35
DecodedLen returns the maximal length.
This length is useful for sizing your buffer but part of the buffer won't be written and thus won't be valid UTF-8.
You have to use only the real written length returned by the Decode function.
l, _ := base64.StdEncoding.Decode(base64Text, []byte(message))
log.Printf("base64: %s\n", base64Text[:l])
Encode []byte as base64 string (to be consistent with stdlib JSON)
The standard library JSON module automatically converts any []byte struct members to base64 encoded strings when marshalling (see https://golang.org/pkg/encoding/json/#Marshal). The YAML library do... More on github.com
3
December 20, 2016Explain why []byte is base64 encoded when marshalled to json?
Base64 is the most widely used text representation of binary data.
More on reddit.com 6
4
November 21, 2019Convert data to base64 encode in go - Stack Overflow
So just apply EncodeToString to ... to []byte suitable for encoding. 2015-06-11T09:00:09.283Z+00:00 ... Save this answer. ... Show activity on this post. You can customise the output of print functions by providing a String() method for your type. Either for the whole Genre or just for the name variable. ... package main import ( "encoding/base64" "fmt" ) type ... More on stackoverflow.com
Is it a good idea to convert images into base64 string and save them in database?
You will get many people saying don't because if not implemented well it can bite ya. Don't be concerned about "optimal", tell yourself "good enough" and "don't let perfect be the enemy of good". But I have done this for several projects (enterprise, mission critical systems) and it works just fine. From the developer standpoint I love it. When I yank the "byte array" from the DB I can just pass it right to the client as-is, just adding on the mime type, super simple. Right now I have a system that stores photos of students at a university and we serve those out with an API. All done in C# and SQL Server. We have probably 50,000 photos and it is lighting fast. That being said I have also stored files in S3 and just stored the name in the DB. I will usually rename the file so S3 stores it efficiently. I like things like s3 better than a file system since you can dedicate a bucket just to this and some sysadmin won't go mucking around. I agree with you on storing the unstructured binary data along with your structured data for simplicity. I had a project once that wrote images to a filesystem. Years later older images were lost due to some file system cleanup process. Over my 25 years programming I have found you cannot guess where the issues will be. Don't optimize until you measure it. If you can build a proof of concept then hammer it, do it. Write a script that inserts and reads images and loop it for a few hours. See what happens. Also if you implement something and a few years later it starts to falter, then refactor. But you need to monitor! This is another place where people get bit, they do something like this and just let it run in a corner until it "just dies for no reason" one day. You or someone needs to care and feed for it. I am going to assume on-prem Microsoft SQL Server, your usage may vary. Use "VARBINARY(MAX)" for the field type https://docs.microsoft.com/en-us/sql/t-sql/data-types/binary-and-varbinary-transact-sql?view=sql-server-ver15 Put it in a table by itself with an id to look it up. Store filename, and filetype(mime-type) too if needed. Slap an index on the id, reference that id in other tables. Critical: Put the table in its own filegroup separate from the other tables. This will allow for faster restores since you can restore the primary filegroup and get your DB back online ASAP, then as it is up and running restore the filegroup with the images. So instead of the whole DB being down for hours, it is up in minutes with only the images being unavailable for hours. https://docs.microsoft.com/en-us/sql/relational-databases/databases/database-files-and-filegroups?view=sql-server-ver15 As with all DBs the filegroups should not be on the system (C) drive, maybe even put the images table filegroup on its own drive with nothing else. Do set a limit on the incoming filesize in your code. Someone could send in a few Blu-ray ISOs and cripple your system. In .NET code you store the image data in a byte array "byte[] " variable. That byte array is what is stored in the varbinary(max) DB field. It is easy to convert the incoming image/file to byte[], just google around for that there are many easy to do it. Design and implement a cleanup process and purge old unneeded records. No one ever seems to do this and the data grows forever until the system is retired/migrated. For small DBs it's not a problem but for this you must go back to your stakeholder and get in writing when you can delete old records then set an automated process or scheduled manual progress to do it. If they need the data long term maybe older data can be moved out of the online system and to an archive or warehouse. Microsoft has some other methods that I have not used. Check those out. https://docs.microsoft.com/en-us/sql/relational-databases/blob/binary-large-object-blob-data-sql-server?view=sql-server-ver15 -- Good luck More on reddit.com
111
46
April 28, 2022gosamples
gosamples.dev โบ tutorials โบ encode a string to base64 in go
๐ Encode a string to Base64 in Go
October 14, 2021 - To encode a string to Base64 in Go, use the EncodeToString() function from the encoding/base64 standard library package. This function takes a byte slice and converts it to a Base64 encoded string, but it can also be used for a string argument by converting it to a byte slice.
GitHub
gist.github.com โบ Xeoncross โบ e83313ac7157c659416676a6044fcd1e
Base 64 encode and decode a byte array in Golang. https://play.golang.org/p/X4z9zq0nXlW ยท GitHub
July 6, 2018 - Base 64 encode and decode a byte array in Golang. https://play.golang.org/p/X4z9zq0nXlW ... This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below.
ZetCode
zetcode.com โบ golang โบ base64
Base64 Encoding and Decoding in Go
July 16, 2026 - The base64.StdEncoding.Encode function encodes a source slice of bytes into a destination slice of bytes using the standard Base64 alphabet.
Golang Docs
golangdocs.com โบ home โบ base64 encoding and decoding in golang
Base64 Encoding and Decoding in Golang - Golang Docs
July 29, 2022 - To convert a string to a base64 we first need to convert it to a byte slice.
GitHub
github.com โบ go-yaml โบ yaml โบ issues โบ 231
Encode []byte as base64 string (to be consistent with stdlib JSON) ยท Issue #231 ยท go-yaml/yaml
December 20, 2016 - The standard library JSON module automatically converts any []byte struct members to base64 encoded strings when marshalling (see https://golang.org/pkg/encoding/json/#Marshal). The YAML library do...
Author: go-yaml
Golang.cafe
golang.cafe โบ blog โบ golang-base64-encode-example
Golang base64 Encode Example | Golang.cafe
April 24, 2022 - // The encoder we will use is the base64.StdEncoding // It requires a byte slice so we cast the string to []byte encodedStr := base64.StdEncoding.EncodeToString([]byte(plainStr)) fmt.Println(encodedStr) // Decoding may return an error, in case the input is not well formed decodedStrAsByteSlice, err := base64.StdEncoding.DecodeString(encodedStr) if err != nil { panic("malformed input") } fmt.Println(string(decodedStrAsByteSlice)) }
Go Packages
pkg.go.dev โบ encoding โบ base64
base64 package - encoding/base64 - Go Packages
September 1, 2026 - It writes at most Encoding.DecodedLen(len(src)) bytes to dst and returns the number of bytes written. The caller must ensure that dst is large enough to hold all the decoded data. If src contains invalid base64 data, it will return the number of bytes successfully written and CorruptInputError.
Freshman Tech
freshman.tech โบ snippets โบ go โบ image-to-base64
How to retrieve the base64 encoding for any image in Go
December 3, 2020 - package main import ( "encoding/base64" "fmt" "io/ioutil" "log" "net/http" ) func toBase64(b []byte) string { return base64.StdEncoding.EncodeToString(b) } func main() { // Read the entire file into a byte slice bytes, err := ioutil.ReadFil...
Go
go.dev โบ src โบ encoding โบ base64 โบ example_test.go
- The Go Programming Language
6 7 package base64_test 8 9 import ( 10 "encoding/base64" 11 "fmt" 12 "os" 13 ) 14 15 func Example() { 16 msg := "Hello, ไธ็" 17 encoded := base64.StdEncoding.EncodeToString([]byte(msg)) 18 fmt.Println(encoded) 19 decoded, err := base64.StdEncoding.DecodeString(encoded) 20 if err != nil { 21 fmt.Println("decode error:", err) 22 return 23 } 24 fmt.Println(string(decoded)) 25 // Output: 26 // SGVsbG8sIOS4lueVjA== 27 // Hello, ไธ็ 28 } 29 30 func ExampleEncoding_EncodeToString() { 31 data := []byte("any + old & data") 32 str := base64.StdEncoding.EncodeToString(data) 33 fmt.Println(str) 34
Base64 Decode and Encode
base64decode.net โบ golang-decodestring
Golang DecodeString() - Base64 Decode
Go lang - func (enc *Encoding) DecodeString(s string) ([]byte, error) - Decode an input String using Base64.
Dot Net Perls
dotnetperls.com โบ base64-go
Go - base64 Example: EncodeToString - Dot Net Perls
With the encoding/base64 package, we can use the EncodeToString func in Go to get a string from a byte slice containing the image.
Google Groups
groups.google.com โบ g โบ golang-nuts โบ c โบ kXMWIfSTix0
encoding/json treats []byte as b64 encoded. Could it not?
December 14, 2013 - Basically the current behavior is that if you have a struct with a []byte field that you pass into the json marshaler, it will represent that in the output json string as the base64 encoded version of what you put in, and if you're unmarshaling into a []byte it will try to base64 decode the ...
gosamples
gosamples.dev โบ tutorials โบ decode base64 to a string in go
๐ Decode Base64 to a string in Go
October 14, 2021 - The StdEncoding is an object representing the standard base64 encoding, as defined in RFC 4648, and the DecodeString() is its method.
Weichou1229
weichou1229.github.io โบ posts โบ golang-base64-encode-and-decode
Golang | Base64 Encode and Decode | WeiChou
August 11, 2023 - package main import ( "encoding/base64" "fmt" "bytes" "encoding/binary" "math" ) func main() { val := 0.123 valToBytes := Float64ToByte(val) fmt.Println("Convert float", val, "to byte array:", valToBytes) base64EncodedStr := base64.StdEncoding.EncodeToString(valToBytes) fmt.Println("Encoded byte array to base64 string: ",base64EncodedStr) decodedToBytes, _ := base64.StdEncoding.DecodeString(base64EncodedStr) fmt.Println("Decode base64 string to float :",Float64frombytes(decodedToBytes)) } func Float64ToByte(f float64) []byte { var buf bytes.Buffer err := binary.Write(&buf, binary.BigEndian, f) if err != nil { fmt.Println("binary.Write failed:", err) } return buf.Bytes() } func Float64frombytes(bytes []byte) float64 { bits := binary.BigEndian.Uint64(bytes) float := math.Float64frombits(bits) return float }
Reddit
reddit.com โบ r/golang โบ explain why []byte is base64 encoded when marshalled to json?
r/golang on Reddit: Explain why []byte is base64 encoded when marshalled to json?
November 21, 2019 -
This is documented in the json package:
โ... []byte encodes as a base64-encoded string ...โ
Iโm curious about the motivation behind this design? Do other languages do this?
I understand that base64 encoding is done to transport binary data through transport mechanisms that are better at handling text. I guess you wouldnโt want a json array because it would be less efficient to marshal/unmarshal vs a string.
Top answer 1 of 3
6
Base64 is the most widely used text representation of binary data.
2 of 3
5
It's because []byte != string if you've come from C or similar and have been using byte as a char replacement. You need some way to safely transport bytes since JSON values can only be string (UTF-8), number, object, array, bool & null.
I don't know about other languages but if you use Array#pack in Ruby to build a 'binary string' then JSON#generate will raise an Encoding::UndefinedConversionError exception if your 'binary string' can't be converted to UTF-8. So in Ruby you need to encode binary data (with base64, an array of integers to use with unpack or whatever) yourself to safely use it in JSON.
GeeksforGeeks
geeksforgeeks.org โบ go language โบ base64-package-in-golang
base64 Package in Golang - GeeksforGeeks
June 22, 2020 - Decoded Bytes: [71 101 101 107 115 102 111 114 71 101 101 107 115] Decoded String: GeeksforGeeks Example 2: ... // Golang program to illustrate // the base64.NewEncoder() function package main import ( "encoding/base64" "fmt" ) func main() { // Input string giveninput := []byte("GeeksforGeeks") // Using EncodeToString() function // Encode the given string result := base64.StdEncoding.EncodeToString(giveninput) fmt.Println("Encoded string: ", result) } Output:
Top answer 1 of 2
6
I am not sure what exactly is not clear from the documentation. Not only it has a clear name which explains states what the method is doing, it also has an example.
package main
import (
"encoding/base64"
"fmt"
)
func main() {
data := []byte("Pop")
str := base64.StdEncoding.EncodeToString(data)
fmt.Println(str) // UG9w
}
Go Playground
2 of 2
0
You can customise the output of print functions by providing a String() method for your type. Either for the whole Genre or just for the name variable.
Example:
package main
import (
"encoding/base64"
"fmt"
)
type Base64String string
func (b Base64String) String() string {
return base64.StdEncoding.EncodeToString([]byte(b))
}
type Genre struct {
Name Base64String
}
func main() {
a := []Genre{Genre{"Pop"}, Genre{"Rock"}}
fmt.Println(a) // prints [{UG9w} {Um9jaw==}]
fmt.Println(string(a[0].Name)) // prints Pop
}