How do I represent a path without query string?
Eg.:
www.example.com/user instead of
www.example.com/user?id=1
The following code didn't work:
Go:
if r.URL.Path[4:] != "" {
//do something
}
func main() {
req, err := http.NewRequest("GET", "http://www.example.com/user?id=1", nil)
if err != nil {
log.Fatal(err)
}
// get host
fmt.Printf("%v\n", req.Host) // Output: www.example.com
// path without query string
fmt.Printf("%v\n", req.URL.Path) // Output: /user
// get query string value by key
fmt.Printf("%v\n", req.URL.Query().Get("id")) // Output: 1
// raw query string
fmt.Printf("%v\n", req.URL.RawQuery) // Output: id=1
}
Go play
To add parameters to an url, you would use Values().
That means, an URL without any parameters would have its 'Values' length set to 0:
if len(r.URL.Query()) == 0 {
}
That should be the same as the r.URL.RawQuery suggested by Dewy Broto in the comments:
if r.URL.RawQuery == "" {
}
Or you can check for the presence if the key 'id' in the Values() map.
if r.URL.Query().Get("id") == "" {
//do something here
}
Related
I have the following simple golang code which retrieves tags from terraform repository:
import (
"github.com/google/go-github/v48/github"
"context"
)
func main() {
client := github.NewClient(nil)
tags, _, _ := client.Repositories.ListTags(context.Background(), "hashicorp", "terraform", nil)
if len(tags) > 0 {
latestTag := tags[0]
fmt.Println(latestTag.Name)
} else {
fmt.Printf("No tags yet")
}
}
Which returns a strange hexadecimal value:
0x1400035c4a0
And I would want to return:
v1.4.0-alpha20221207
Following the official docs, the function ListTags should return the name encoded into a struct:
https://pkg.go.dev/github.com/google/go-github/github#RepositoriesService.ListTags
Many thanks
I did try to execute a simple GET request https://api.github.com/repos/hashicorp/terraform/tags and I can see that the github api returns the tags correctly
IDK why, but I realize the latestTag.Name is a pointer and what you're printing is the address of the memory: 0x1400035c4a0.
You just need to dereference it:
fmt.Println(*latestTag.Name)
Bonus, check error with if condition that is returned by the function call to avoid having to go something like this:
tags, response, err := client.Repositories.ListTags(context.Background(), "hashicorp", "terraform", nil)
fmt.Println(response)
if err != nil {
fmt.Println(err)
} else {
if len(tags) > 0 {
latestTag := tags[0]
fmt.Println(*latestTag.Name)
} else {
fmt.Printf("No tags yet")
}
}
Im working with for each loop and var of information and filtering it by A) regex.matchString B)Timecomparrison. The filtering works well and I have the data I need but currently I'm outputting it to screen via fmt.Println in part of the loop. My goal is to take that data and build another var with the now filtered list. I guess I need to make a new variable and add to it? But how do I return that and something I can use later?
Any assistance is appreciated.
for _, thing := range things {
if thing.element1 != nil {
matched, err := regexp.MatchString(z, element1)
if err != nil {
fmt.Println(err)
}
if matched {
if timecomparrison(element2, a) {
// this is a section that needs to be added new var and returned as a var
fmt.Println("****")
fmt.Println("element1:", element1)
fmt.Println("element2:", element2)
}
}
}
}
}
I think you need something like this.
type Thing struct {
element1 string
element2 string
}
func filter() []Thing {
things := []Thing{
{element1: "element1", element2: "element2"},
}
var result []Thing
regex := "/{}d/"
date := time.Now
for _, thing := range things {
if thing.element1 != nil {
matched, err := regexp.MatchString(regex, thing.element1)
if err != nil {
fmt.Println(err)
}
if matched {
if timeComparison(thing.element2, date) {
// this is a section that needs to be added new var and returned as a var
fmt.Println("****")
fmt.Println("element1:", thing.element1)
fmt.Println("element2:", thing.element2)
result = append(result, thing)
}
}
}
}
return result
}
I cleaned the code, added a type and some data, fixed some issues and renamed some things, but you should get the idea :)
Is there a way to search for a value in Hashicorp Vault? I am trying to write Golang code to search and list all locations a value appears in vault. It would be similar to golang's walk function on directories. Does anyone have a good approach for this? I was thinking of using concurrency to search vault for a value. Thank you
Below is a sample of the code I came up with. I am looking on how to make this faster by using concurrency. Is there a way to traverse a directory concurrently?
func walkDir(client *api.Client, path string) {
var value *api.Secret
var err error
if path != "" {
value, err = client.Logical().List(path)
} else {
path = vault_path
value, err = client.Logical().List(path)
}
if err != nil {
fmt.Println(err)
}
var datamap map[string]interface{}
datamap = value.Data
data := datamap["keys"].([]interface{})
for _, item := range data {
itemString := item.(string)
if strings.HasSuffix(itemString, "/") {
walkDir(client, path+itemString)
} else {
//its a secret
data := read(client, path+itemString)
if *searchKey!="" && searchForKey(data,*searchKey){
fmt.Println(path + itemString)
}
if *searchValue!="" && searchForValue(data,*searchValue){
fmt.Println(path + itemString)
}
}
}
}
func read(client *api.Client, path string) map[string]interface{} {
value, err := client.Logical().Read(path)
if err != nil {
fmt.Println(err)
}
values := value.Data
return values
}
func searchForValue(mapp map[string]interface{}, searchValue string) bool {
for _, value := range mapp {
if searchValue == value {
return true
}
}
return false
}
func searchForKey(mapp map[string]interface{}, searchKey string) bool {
for key := range mapp {
if searchKey == key {
return true
}
}
return false
}
You can LIST "directories" in Vault (I'm assuming you're just looking at the kv engine). So treat it somewhat like a regular file-system: start at the root, list the entries, check the contents of each of them for that value, then iterate through each entry, listing its contents, and so forth.
https://www.vaultproject.io/api-docs/secret/kv/kv-v1#list-secrets
I have this json that I convert to:
var leerCHAT []interface{}
but I am going through crazy hoops to get to any point on that map inside map and inside map crazyness, specially because some results are different content.
this is the Json
[
null,
null,
"hub:zWXroom",
"presence_diff",
{
"joins":{
"f718a187-6e96-4d62-9c2d-67aedea00000":{
"metas":[
{
"context":{},
"permissions":{},
"phx_ref":"zNDwmfsome=",
"phx_ref_prev":"zDMbRTmsome=",
"presence":"lobby",
"profile":{},
"roles":{}
}
]
}
},
"leaves":{}
}
]
I need to get to profile then inside there is a "DisplayName" field.
so I been doing crazy hacks.. and even like this I got stuck half way...
First is an array so I can just do something[elementnumber]
then is when the tricky mapping starts...
SORRY about all the prints etc is to debug and see the number of elements I am getting back.
if leerCHAT[3] == "presence_diff" {
var id string
presence := leerCHAT[4].(map[string]interface{})
log.Printf("algo: %v", len(presence))
log.Printf("algo: %s", presence["joins"])
vamos := presence["joins"].(map[string]interface{})
for i := range vamos {
log.Println(i)
id = i
}
log.Println(len(vamos))
vamonos := vamos[id].(map[string]interface{})
log.Println(vamonos)
log.Println(len(vamonos))
metas := vamonos["profile"].(map[string]interface{}) \\\ I get error here..
log.Println(len(metas))
}
so far I can see all the way to the meta:{...} but can't continue with my hacky code into what I need.
NOTICE: that since the id after Joins: and before metas: is dynamic I have to get it somehow since is always just one element I did the for range loop to grab it.
The array element at index 3 describes the type of the variant JSON at index 4.
Here's how to decode the JSON to Go values. First, declare Go types for each of the variant parts of the JSON:
type PrescenceDiff struct {
Joins map[string]*Presence // declaration of Presence type to be supplied
Leaves map[string]*Presence
}
type Message struct {
Body string
}
Declare a map associating the type string to the Go type:
var messageTypes = map[string]reflect.Type{
"presence_diff": reflect.TypeOf(&PresenceDiff{}),
"message": reflect.TypeOf(&Message{}),
// add more types here as needed
}
Decode the variant part to a raw message. Use use the name in the element at index 3 to create a value of the appropriate Go type and decode to that value:
func decode(data []byte) (interface{}, error) {
var messageType string
var raw json.RawMessage
v := []interface{}{nil, nil, nil, &messageType, &raw}
err := json.Unmarshal(data, &v)
if err != nil {
return nil, err
}
if len(raw) == 0 {
return nil, errors.New("no message")
}
t := messageTypes[messageType]
if t == nil {
return nil, fmt.Errorf("unknown message type: %q", messageType)
}
result := reflect.New(t.Elem()).Interface()
err = json.Unmarshal(raw, result)
return result, err
}
Use type switches to access the variant part of the message:
defer ws.Close()
for {
_, data, err := ws.ReadMessage()
if err != nil {
log.Printf("Read error: %v", err)
break
}
v, err := decode(data)
if err != nil {
log.Printf("Decode error: %v", err)
continue
}
switch v := v.(type) {
case *PresenceDiff:
fmt.Println(v.Joins, v.Leaves)
case *Message:
fmt.Println(v.Body)
default:
fmt.Printf("type %T not handled\n", v)
}
}
Run it on the playground.
I have created an object mapping in Go that is not relational, it is very simple.
I have several structs that looks like this:
type Message struct {
Id int64
Message string
ReplyTo sql.NullInt64 `db:"reply_to"`
FromId int64 `db:"from_id"`
ToId int64 `db:"to_id"`
IsActive bool `db:"is_active"`
SentTime int64 `db:"sent_time"`
IsViewed bool `db:"is_viewed"`
Method string `db:"-"`
AppendTo int64 `db:"-"`
}
To create a new message I just run this function:
func New() *Message {
return &Message{
IsActive: true,
SentTime: time.Now().Unix(),
Method: "new",
}
}
And then I have a message_crud.go file for this struct that looks like this:
To find a message by a unique column (for example by id) I run this function:
func ByUnique(column string, value interface{}) (*Message, error) {
query := fmt.Sprintf(`
SELECT *
FROM message
WHERE %s = ?
LIMIT 1;
`, column)
message := &Message{}
err := sql.DB.QueryRowx(query, value).StructScan(message)
if err != nil {
return nil, err
}
return message, nil
}
And to save a message (insert or update in the database) I run this method:
func (this *Message) save() error {
s := ""
if this.Id == 0 {
s = "INSERT INTO message SET %s;"
} else {
s = "UPDATE message SET %s WHERE id=:id;"
}
query := fmt.Sprintf(s, sql.PlaceholderPairs(this))
nstmt, err := sql.DB.PrepareNamed(query)
if err != nil {
return err
}
res, err := nstmt.Exec(*this)
if err != nil {
return err
}
if this.Id == 0 {
lastId, err := res.LastInsertId()
if err != nil {
return err
}
this.Id = lastId
}
return nil
}
The sql.PlaceholderPairs() function looks like this:
func PlaceholderPairs(i interface{}) string {
s := ""
val := reflect.ValueOf(i).Elem()
count := val.NumField()
for i := 0; i < count; i++ {
typeField := val.Type().Field(i)
tag := typeField.Tag
fname := strings.ToLower(typeField.Name)
if fname == "id" {
continue
}
if t := tag.Get("db"); t == "-" {
continue
} else if t != "" {
s += t + "=:" + t
} else {
s += fname + "=:" + fname
}
s += ", "
}
s = s[:len(s)-2]
return s
}
But every time I create a new struct, for example a User struct I have to copy paste the "crud section" above and create a user_crud.go file and replace the words "Message" with "User", and the words "message" with "user". I repeat alot of code and it is not very dry. Is there something I could do to not repeat this code for things I would reuse? I always have a save() method, and always have a function ByUnique() where I can return a struct and search by a unique column.
In PHP this was easy because PHP is not statically typed.
Is this possible to do in Go?
Your ByUnique is almost generic already. Just pull out the piece that varies (the table and destination):
func ByUnique(table string, column string, value interface{}, dest interface{}) error {
query := fmt.Sprintf(`
SELECT *
FROM %s
WHERE %s = ?
LIMIT 1;
`, table, column)
return sql.DB.QueryRowx(query, value).StructScan(dest)
}
func ByUniqueMessage(column string, value interface{}) (*Message, error) {
message := &Message{}
if err := ByUnique("message", column, value, &message); err != nil {
return nil, err
}
return message, error
}
Your save is very similar. You just need to make a generic save function along the lines of:
func Save(table string, identifier int64, source interface{}) { ... }
Then inside of (*Message)save, you'd just call the general Save() function. Looks pretty straightforward.
Side notes: do not use this as the name of the object inside a method. See the link from #OneOfOne for more on that. And do not get obsessed about DRY. It is not a goal in itself. Go focuses on code being simple, clear, and reliable. Do not create something complicated and fragile just to avoid typing a simple line of error handling. This doesn't mean that you shouldn't extract duplicated code. It just means that in Go it is usually better to repeat simple code a little bit rather than create complicated code to avoid it.
EDIT: If you want to implement Save using an interface, that's no problem. Just create an Identifier interface.
type Ider interface {
Id() int64
SetId(newId int64)
}
func (msg *Message) Id() int64 {
return msg.Id
}
func (msg *Message) SetId(newId int64) {
msg.Id = newId
}
func Save(table string, source Ider) error {
s := ""
if source.Id() == 0 {
s = fmt.Sprintf("INSERT INTO %s SET %%s;", table)
} else {
s = fmt.Sprintf("UPDATE %s SET %%s WHERE id=:id;", table)
}
query := fmt.Sprintf(s, sql.PlaceholderPairs(source))
nstmt, err := sql.DB.PrepareNamed(query)
if err != nil {
return err
}
res, err := nstmt.Exec(source)
if err != nil {
return err
}
if source.Id() == 0 {
lastId, err := res.LastInsertId()
if err != nil {
return err
}
source.SetId(lastId)
}
return nil
}
func (msg *Message) save() error {
return Save("message", msg)
}
The one piece that might blow up with this is the call to Exec. I don't know what package you're using, and it's possible that Exec won't work correctly if you pass it an interface rather than the actual struct, but it probably will work. That said, I'd probably just pass the identifier rather than adding this overhead.
You probably want to use an ORM.
They eliminate a lot of the boilerplate code you're describing.
See this question for "What is an ORM?"
Here is a list of ORMs for go: https://github.com/avelino/awesome-go#orm
I have never used one myself, so I can't recommend any. The main reason is that an ORM takes a lot of control from the developer and introduces a non-negligible performance overhead. You need to see for yourself if they fit your use-case and/or if you are comfortable with the "magic" that's going on in those libraries.
I don't recommend doing this, i personally would prefer being explicit about scanning into structs and creating queries.
But if you really want to stick to reflection you could do:
func ByUnique(obj interface{}, column string, value interface{}) error {
// ...
return sql.DB.QueryRowx(query, value).StructScan(obj)
}
// Call with
message := &Message{}
ByUnique(message, ...)
And for your save:
type Identifiable interface {
Id() int64
}
// Implement Identifiable for message, etc.
func Save(obj Identifiable) error {
// ...
}
// Call with
Save(message)
The approach i use and would recommend to you:
type Redirect struct {
ID string
URL string
CreatedAt time.Time
}
func FindByID(db *sql.DB, id string) (*Redirect, error) {
var redirect Redirect
err := db.QueryRow(
`SELECT "id", "url", "created_at" FROM "redirect" WHERE "id" = $1`, id).
Scan(&redirect.ID, &redirect.URL, &redirect.CreatedAt)
switch {
case err == sql.ErrNoRows:
return nil, nil
case err != nil:
return nil, err
}
return &redirect, nil
}
func Save(db *sql.DB, redirect *Redirect) error {
redirect.CreatedAt = time.Now()
_, err := db.Exec(
`INSERT INTO "redirect" ("id", "url", "created_at") VALUES ($1, $2, $3)`,
redirect.ID, redirect.URL, redirect.CreatedAt)
return err
}
This has the advantage of using the type system and mapping only things it should actually map.