I am calling this code:
package multicall
import (
"fmt"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/ethclient"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
)
var multicallContractAddress = common.HexToAddress("0x5e227AD1969Ea493B43F840cfF78d08a6fc17796")
var multicallContractEthBalanceSelector = "4d2301cc"
func GetBalances(addresses []string, ETHProviderURL string) ([]string, error) {
ethProvider, err := ethclient.Dial(ETHProviderURL)
if err != nil {
panic(err)
}
multicallContract, err := NewMulticallCaller(multicallContractAddress, ethProvider)
if err != nil {
panic(err)
}
fmt.Println("multicallContract: ", multicallContract)
var calls = []MulticallCall{}
for _, address := range addresses {
hashAddress := common.HexToHash(address)
call := MulticallCall{multicallContractAddress, []byte("0x"+multicallContractEthBalanceSelector+hashAddress.String()[2:])}
calls = append(calls, call)
}
fmt.Println(string(calls[0].CallData))
var results []byte
err = multicallContract.contract.Call(&bind.CallOpts{}, results, "aggregate", common.Hex2Bytes(addresses[0]))
if err != nil {
panic(err)
}
fmt.Println("Result: ", &results)
return nil, nil
}
like this:
multicall.GetBalances([]string{"<MY_ADDRESS>"}, "<INFURA_API_KEY>")
And it returns this error:
# github.com/mteam88/keyswarm/multicall
multicall/multicall.go:37:58: cannot use results (variable of type []byte) as type *[]interface{} in argument to multicallContract.contract.Call
It seems like results should be a specific type/interface (maybe []uint8) but I can't seem to pass it like that to the Call function.
I have tried tons of things and I can't seem to get it. My Google diving has uncovered this Why am I getting a compile error 'cannot use ... as type uint8 in argument to ...' when the parameter is an int which led me to my previous assumption.
If you -1 please comment (:
Please provide links to relevant documentation in your answer.
NOTE: https://github.com/mteam88/keyswarm/blob/multicall/multicall/multicallContract.go is the location of the defenitions of MulticallCall and other Multicall prefixed defenitions.
So I currently have a function that will take in a string APIKey to check it against my Mongo collection. If nothing is found (not authenticated), it returns false - if a user is found, it returns true. My problem, however, is I'm unsure how to integrate this with a Martini POST route. Here is my code:
package main
import (
"context"
"fmt"
"log"
"os"
"github.com/go-martini/martini"
_ "github.com/joho/godotenv/autoload"
"go.mongodb.org/mongo-driver/bson"
"go.mongodb.org/mongo-driver/mongo"
"go.mongodb.org/mongo-driver/mongo/options"
)
type User struct {
Name string
APIKey string
}
func validateAPIKey(users *mongo.Collection, APIKey string) bool {
var user User
filter := bson.D{{"APIKey", APIKey}}
if err := users.FindOne(context.TODO(), filter).Decode(&user); err != nil {
fmt.Printf("Found 0 results for API Key: %s\n", APIKey)
return false
}
fmt.Printf("Found: %s\n", user.Name)
return true
}
func uploadHandler() {
}
func main() {
mongoURI := os.Getenv("MONGO_URI")
mongoOptions := options.Client().ApplyURI(mongoURI)
client, _ := mongo.Connect(context.TODO(), mongoOptions)
defer client.Disconnect(context.TODO())
if err := client.Ping(context.TODO(), nil); err != nil {
log.Fatal(err, "Unable to access MongoDB server, exiting...")
}
// users := client.Database("sharex_api").Collection("authorized_users") // commented out when testing to ignore unused warnings
m := martini.Classic()
m.Post("/api/v1/upload", uploadHandler)
m.RunOnAddr(":8085")
}
The validateAPIKey function works exactly as intended if tested alone, I am just unsure how I would run this function for a specific endpoint (in this case, /api/v1/upload).
I am using the atom IDE, and for some reason whenever I add this to my imports:
"github.com/nlopes/slack"
And save the file, it removes the import. So I'm not sure why but it isn't finding the InteractionCallback type in the library?
I copied this code from the example:
func unmarshalSuggestionCallback(j string) (*InteractionCallback, error) {
callback := &InteractionCallback{}
if err := json.Unmarshal([]byte(j), &callback); err != nil {
return nil, err
}
return callback, nil
}
I am getting this error:
undefined: InteractionCallback
How can I tell if my library I just downloaded has the type defined? Or am I referencing the type incorrectly?
Please use this command in your terminal:
go get -u github.com/nlopes/slack
After that try to run this code:
package main
import (
"encoding/json"
"fmt"
"github.com/nlopes/slack"
)
func unmarshalSuggestionCallback(j string) (*slack.InteractionCallback, error) {
callback := &slack.InteractionCallback{}
if err := json.Unmarshal([]byte(j), &callback); err != nil {
return nil, err
}
return callback, nil
}
func main() {
callback,_:=unmarshalSuggestionCallback(`{"type":"callback"}`)
fmt.Println(callback.Type)
}
Everything should work fine, I have checked in my PC
You need to specify from which package InteractionCallback comes from, in your case its slack package - slack.InteractionCallback
I'm trying to write a tiny application in Go that can send an HTTP request to all IP addresses in hopes to find a specific content. The issue is that the application seems to crash in a very peculiar way when the call is executed asynchronously.
ip/validator.go
package ip
import (
"io/ioutil"
"net/http"
"regexp"
"time"
)
type ipValidator struct {
httpClient http.Client
path string
exp *regexp.Regexp
confirmationChannel *chan string
}
func (this *ipValidator) validateUrl(url string) bool {
response, err := this.httpClient.Get(url)
if err != nil {
return false
}
defer response.Body.Close()
if response.StatusCode != http.StatusOK {
return false
}
bodyBytes, _ := ioutil.ReadAll(response.Body)
result := this.exp.Match(bodyBytes)
if result && this.confirmationChannel != nil {
*this.confirmationChannel <- url
}
return result
}
func (this *ipValidator) ValidateIp(addr ip) bool {
httpResult := this.validateUrl("http://" + addr.ToString() + this.path)
httpsResult := this.validateUrl("https://" + addr.ToString() + this.path)
return httpResult || httpsResult
}
func (this *ipValidator) GetSuccessChannel() *chan string {
return this.confirmationChannel
}
func NewIpValidadtor(path string, exp *regexp.Regexp) ipValidator {
return newValidator(path, exp, nil)
}
func NewAsyncIpValidator(path string, exp *regexp.Regexp) ipValidator {
c := make(chan string)
return newValidator(path, exp, &c)
}
func newValidator(path string, exp *regexp.Regexp, c *chan string) ipValidator {
httpClient := http.Client{
Timeout: time.Second * 2,
}
return ipValidator{httpClient, path, exp, c}
}
main.go
package main
import (
"./ip"
"fmt"
"os"
"regexp"
)
func processOutput(c *chan string) {
for true {
url := <- *c
fmt.Println(url)
}
}
func main() {
args := os.Args[1:]
fmt.Printf("path: %s regex: %s", args[0], args[1])
regexp, regexpError := regexp.Compile(args[1])
if regexpError != nil {
fmt.Println("The provided regexp is not valid")
return
}
currentIp, _ := ip.NewIp("172.217.22.174")
validator := ip.NewAsyncIpValidator(args[0], regexp)
successChannel := validator.GetSuccessChannel()
go processOutput(successChannel)
for currentIp.HasMore() {
go validator.ValidateIp(currentIp)
currentIp = currentIp.Increment()
}
}
Note the line that says go validator.ValidateIp(currentIp) in main.go. Should I remove the word "go" to execute everything within the main routine, the code works as expected -> it sends requests to IP addresses starting 172.217.22.174 and should one of them return a legitimate result that matches the regexp that the ipValidator was initialized with, the URL is passed to the channel and the value is printed out by processOutput function from main.go. The issue is that simply adding go in front of validator.ValidateIp(currentIp) breaks that functionality. In fact, according to the debugger, I never seem to go past the line that says response, err := this.httpClient.Get(url) in validator.go.
The struggle is real. Should I decide to scan the whole internet, there's 256^4 IP addresses to go through. It will take years, unless I find a way to split the process into multiple routines.
Is there a native way for inplace url parameters in native Go?
For Example, if I have a URL: http://localhost:8080/blob/123/test I want to use this URL as /blob/{id}/test.
This is not a question about finding go libraries. I am starting with the basic question, does go itself provide a basic facility to do this natively.
There is no built in simple way to do this, however, it is not hard to do.
This is how I do it, without adding a particular library. It is placed in a function so that you can invoke a simple getCode() function within your request handler.
Basically you just split the r.URL.Path into parts, and then analyse the parts.
// Extract a code from a URL. Return the default code if code
// is missing or code is not a valid number.
func getCode(r *http.Request, defaultCode int) (int, string) {
p := strings.Split(r.URL.Path, "/")
if len(p) == 1 {
return defaultCode, p[0]
} else if len(p) > 1 {
code, err := strconv.Atoi(p[0])
if err == nil {
return code, p[1]
} else {
return defaultCode, p[1]
}
} else {
return defaultCode, ""
}
}
Well, without external libraries you can't, but may I recommend two excellent ones:
httprouter - https://github.com/julienschmidt/httprouter - is extremely fast and very lightweight. It's faster than the standard library's router, and it creates 0 allocations per call, which is great in a GCed language.
Gorilla Mux - http://www.gorillatoolkit.org/pkg/mux -
Very popular, nice interface, nice community.
Example usage of httprouter:
func Hello(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
fmt.Fprintf(w, "hello, %s!\n", ps.ByName("name"))
}
func main() {
router := httprouter.New()
router.GET("/hello/:name", Hello)
log.Fatal(http.ListenAndServe(":8080", router))
}
What about trying using regex, and find a named group in your url, like playground:
package main
import (
"fmt"
"net/url"
"regexp"
)
var myExp = regexp.MustCompile(`/blob/(?P<id>\d+)/test`) // use (?P<id>[a-zA-Z]+) if the id is alphapatic
func main() {
s := "http://localhost:8080/blob/123/test"
u, err := url.Parse(s)
if err != nil {
panic(err)
}
fmt.Println(u.Path)
match := myExp.FindStringSubmatch(s) // or match := myExp.FindStringSubmatch(u.Path)
result := make(map[string]string)
for i, name := range myExp.SubexpNames() {
if i != 0 && name != "" {
result[name] = match[i]
}
}
fmt.Printf("id: %s\n", result["id"])
}
output
/blob/123/test
id: 123
Below full code to use it with url, that is receiving http://localhost:8000/hello/John/58 and returning http://localhost:8000/hello/John/58:
package main
import (
"fmt"
"net/http"
"regexp"
"strconv"
)
var helloExp = regexp.MustCompile(`/hello/(?P<name>[a-zA-Z]+)/(?P<age>\d+)`)
func hello(w http.ResponseWriter, req *http.Request) {
match := helloExp.FindStringSubmatch(req.URL.Path)
if len(match) > 0 {
result := make(map[string]string)
for i, name := range helloExp.SubexpNames() {
if i != 0 && name != "" {
result[name] = match[i]
}
}
if _, err := strconv.Atoi(result["age"]); err == nil {
fmt.Fprintf(w, "Hello, %v year old named %s!", result["age"], result["name"])
} else {
fmt.Fprintf(w, "Sorry, not accepted age!")
}
} else {
fmt.Fprintf(w, "Wrong url\n")
}
}
func main() {
http.HandleFunc("/hello/", hello)
http.ListenAndServe(":8090", nil)
}
How about writing your own url generator (extend net/url a little bit) as below.
// --- This is how does it work like --- //
url, _ := rest.NewURLGen("http", "stack.over.flow", "1234").
Pattern(foo/:foo_id/bar/:bar_id).
ParamQuery("foo_id", "abc").
ParamQuery("bar_id", "xyz").
ParamQuery("page", "1").
ParamQuery("offset", "5").
Do()
log.Printf("url: %s", url)
// url: http://stack.over.flow:1234/foo/abc/bar/xyz?page=1&offset=5
// --- Your own url generator would be like below --- //
package rest
import (
"log"
"net/url"
"strings"
"straas.io/base/errors"
"github.com/jinzhu/copier"
)
// URLGen generates request URL
type URLGen struct {
url.URL
pattern string
paramPath map[string]string
paramQuery map[string]string
}
// NewURLGen new a URLGen
func NewURLGen(scheme, host, port string) *URLGen {
h := host
if port != "" {
h += ":" + port
}
ug := URLGen{}
ug.Scheme = scheme
ug.Host = h
ug.paramPath = make(map[string]string)
ug.paramQuery = make(map[string]string)
return &ug
}
// Clone return copied self
func (u *URLGen) Clone() *URLGen {
cloned := &URLGen{}
cloned.paramPath = make(map[string]string)
cloned.paramQuery = make(map[string]string)
err := copier.Copy(cloned, u)
if err != nil {
log.Panic(err)
}
return cloned
}
// Pattern sets path pattern with placeholder (format `:<holder_name>`)
func (u *URLGen) Pattern(pattern string) *URLGen {
u.pattern = pattern
return u
}
// ParamPath builds path part of URL
func (u *URLGen) ParamPath(key, value string) *URLGen {
u.paramPath[key] = value
return u
}
// ParamQuery builds query part of URL
func (u *URLGen) ParamQuery(key, value string) *URLGen {
u.paramQuery[key] = value
return u
}
// Do returns final URL result.
// The result URL string is possible not escaped correctly.
// This is input for `gorequest`, `gorequest` will handle URL escape.
func (u *URLGen) Do() (string, error) {
err := u.buildPath()
if err != nil {
return "", err
}
u.buildQuery()
return u.String(), nil
}
func (u *URLGen) buildPath() error {
r := []string{}
p := strings.Split(u.pattern, "/")
for i := range p {
part := p[i]
if strings.Contains(part, ":") {
key := strings.TrimPrefix(p[i], ":")
if val, ok := u.paramPath[key]; ok {
r = append(r, val)
} else {
if i != len(p)-1 {
// if placeholder at the end of pattern, it could be not provided
return errors.Errorf("placeholder[%s] not provided", key)
}
}
continue
}
r = append(r, part)
}
u.Path = strings.Join(r, "/")
return nil
}
func (u *URLGen) buildQuery() {
q := u.URL.Query()
for k, v := range u.paramQuery {
q.Set(k, v)
}
u.RawQuery = q.Encode()
}
With net/http the following would trigger when calling localhost:8080/blob/123/test
http.HandleFunc("/blob/", yourHandlerFunction)
Then inside yourHandlerFunction, manually parse r.URL.Path to find 123.
Note that if you don't add a trailing / it won't work. The following would only trigger when calling localhost:8080/blob:
http.HandleFunc("/blob", yourHandlerFunction)
As of 19-Sep-22, with go version 1.19, instance of http.request URL has a method called Query, which will return a map, which is a parsed query string.
func helloHandler(res http.ResponseWriter, req *http.Request) {
// when request URL is `http://localhost:3000/?first=hello&second=world`
fmt.Println(req.URL.Query()) // outputs , map[second:[world] first:[hello]]
res.Write([]byte("Hello World Web"))
}
No way without standard library. Why you don't want to try some library? I think its not so hard to use it, just go get bla bla bla
I use Beego. Its MVC style.
how about a simple utility function ?
func withURLParams(u url.URL, param, val string) url.URL{
u.Path = strings.ReplaceAll(u.Path, param, val)
return u
}
you can use it like this:
u, err := url.Parse("http://localhost:8080/blob/:id/test")
if err != nil {
return nil, err
}
u := withURLParams(u, ":id","123")
// now u.String() is http://localhost:8080/blob/123/test
If you need a framework and you think it will be slow because it's 'bigger' than a router or net/http, then you 're wrong.
Iris is the fastest go web framework that you will ever find, so far according to all benchmarks.
Install by
go get gopkg.in/kataras/iris.v6
Django templates goes easy with iris:
import (
"gopkg.in/kataras/iris.v6"
"gopkg.in/kataras/iris.v6/adaptors/httprouter"
"gopkg.in/kataras/iris.v6/adaptors/view" // <-----
)
func main() {
app := iris.New()
app.Adapt(iris.DevLogger())
app.Adapt(httprouter.New()) // you can choose gorillamux too
app.Adapt(view.Django("./templates", ".html")) // <-----
// RESOURCE: http://127.0.0.1:8080/hi
// METHOD: "GET"
app.Get("/hi", hi)
app.Listen(":8080")
}
func hi(ctx *iris.Context){
ctx.Render("hi.html", iris.Map{"Name": "iris"})
}