When ever I try to deploy my smart contract to test, I receive an error indicating "transaction type not supported". Below is the source code. I'm trying to deploy my simple smart contract using abigen's Go bindings.
Versions:
go1.16.7
Solidity 0.8.9+commit.e5eed63a.Darwin.appleclang
Solidity Source code. I've tested this in Remix and it has worked everytime:
contract SendMSG {
function Send(address sendTo, bytes calldata message) public {
OtherContract other = OtherContract(sendTo);
other.send(message);
}
}
This is the contract I'm using ignore syntax errors as it may be human error while anonymizing.
I then run this line to develop the abi bindings and put them in the right place. I can confirm this works as the go file is always created:
abigen --sol ../../contracts/Contract.sol --pkg Contract --out Contract.go
Go Code. I believe there shouldn't be any issues. I'm using a simulated backend/blockchain for testing:
package Contract
import (
"testing"
"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/common"
"math/big"
)
// Test inbox contract gets deployed correctly
func TestMain(t *testing.T) {
//Setup simulated block chain
key, _ := crypto.GenerateKey()
auth := bind.NewKeyedTransactor(key)
alloc := make(core.GenesisAlloc)
alloc[auth.From] = core.GenesisAccount{Balance: big.NewInt(133700000)}
gasLimit := 300000
sim := backends.NewSimulatedBackend(alloc, gasLimit)
//Deploy contract
address, _, _, err := DeploySameBindings(
auth,
sim,
)
// commit all pending transactions
blockchain.Commit()
if err != nil {
t.Fatalf("Failed to deploy the contract: %v", err)
}
}
Always, it gives the same err, "transaction type not supported". I know the line where the error origin [GitHub]. From there, maybe I didn't set a payment mechanism? But all the tutorials I've seen didn't include one and if anyone could provide a guide as to how to do that.
Thank you.
This was stupid.
Geth updated their code and there weren't any tutorials so for anyone hoping to run a simulated background here's the answer:
You have to set the gas price manually. Taking this on after defining client and auth fixes it.
gasPrice, err := client.SuggestGasPrice(context.Background())
auth.GasPrice=gasPrice
I'm currently using gorm and gin framework. I wonder what would happen if an error happened and my app didn't handle it?
Example:
if err := db.Where("name = ?", "jinzhu").First(&user).Error; err != nil {
// error handling...
}
In the above example, the error is being handled.
if db.Model(&user).Related(&credit_card).RecordNotFound() {
// no credit card found error handling
}
In the next example above, only the RecordNotFound() error is being handled, but what if it throws a different error? what will happen?
Will my app automatically respond with a 500 server internal error and will the app keep on running properly?
In the next example above, only the RecordNotFound() error is being handled, but what if it throws a different error?
If you won't catch the error it will continue on the code. Error is not a special type it's a simple struct
err := FunctionThatReturnsError()
if err == myError.RecordNotFound() { // if err is not RecordNotFound then it won't enter the if simple as that.
// Do something.
}
// continue code.
Will my app automatically respond with a 500 server internal error and will the app keep on running properly?
There will be no response if the go routine doesn't panic or you return a response. If you want to handle it you can do:
err := FunctionThatReturnsError()
if err == myError.RecordNotFound() {
panic("RecordNotFound")
}
or
err := FunctionThatReturnsError()
if err == myError.RecordNotFound() {
c.JSON(500, "Record not found"}
}
I don't recommend the panic method. If you're curious google why.
Go doesn't have exceptions. Instead of catching exceptions, you get errors via return values from functions. So there's no throwing or anything special going on behind the scenes, just a function that returns an error value, and like any other return value - you can discard it.
I wouldn't recommend discarding errors though. If you feel lazy or lost about what to do with an error - just log it:
log.Error(err)
You never know if an error you discarded is causing this mysterious bug you can swear is coming from anywhere but your own code.
I wonder what would happen if an error happened and my app didn't handle it?
Then the state of the app is undefined. If you don't check error values your app will be using values which are undefined (probably nil for pointers and "zeros" for values) or assuming that side effect occurred but it might not.
Let's say you have a function with signature func CreateStruct() (T, err)
and call it like that t, _ := CreateStruct() (not checking for error) you should not expect t variable to have a proper value set.
If you have function like func Update() err and you call it without error checking then you can't know whether update was performed or not.
Of course everything depends on API and implementation. But you get the idea.
but what if it throws a different error?
It's impossible. There is not throwing error mechanism in Go. Error can only be returned as a normal value.
You should never be lazy with handling errors. It's very important part of programming and Go makes it easier to realize.
Hi I'm trying to wrap my head around what seems to be a problem with multibyte support in this open source library (https://github.com/carbocation/go-instagram/). I am using the code below to retrieve information about the tag blue in swedish. How ever I get an empty array when trying.
fmt.Println("Starting instagram download.")
client := instagram.NewClient(nil)
client.ClientID = "myid"
media, _, _ := client.Tags.RecentMedia("blå", nil)
fmt.Println(media)
I have tried using the api trough the browser and there are several pictures tagged with the tag. I have also tried using the code snippet with tags in English like blue and that returns the latest pictures as well. I would be glad if any one could explain why this might happen. Id like to update the lib so it supports multi-byte but I haven't got the go knowledge required. Is this a go problem or a problem with the library?
Thank you
The problem is in validTagName():
// Strip out things we know Instagram won't accept. For example, hyphens.
func validTagName(tagName string) (bool, error) {
//\W matches any non-word character
reg, err := regexp.Compile(`\W`)
if err != nil {
return false, err
}
if reg.MatchString(tagName) {
return false, nil
}
return true, nil
}
In Go, \W matches precisely [^0-9A-Za-z_]. This validation check is incorrect.
I have a short Go program that runs the go list -json command for several packages, stores the output of each run of the command in a json.RawMessage, appends each json.RawMessage into a slice of json.RawMessages, and then returns the result to the server after concatenating each of the json.RawMessages together and compacting the json. However, there is an error message that gets produced when I run json.Compact that I can't locate the source of. Googling this error message reveals that most people who seem to encounter it--whether it's for an invalid , or some other character--have a hard time finding the source of it.
invalid character ',' looking for beginning of value
The code with comments is available to view here on play.golang.org (although it won't run there) and also below.
Question: can you explain the source of this error and how to prevent it?
(Note, some of the packages were included just for testing purposes)
package main
import (
"expvar"
"encoding/json"
"bytes"
"fmt"
"github.com/go-martini/martini"
"github.com/zenazn/goji"
"github.com/zenazn/goji/web"
"go/build"
"log"
"math/rand"
"net/http"
_ "net/http/pprof"
"os/exec"
)
type myType struct {
J []json.RawMessage
}
var pack map[string]string
type GoList struct {
Imports []string
}
type Import struct {
Dir string
ImportPath string
Name string
Target string
Standard bool
Root string
GoFiles []string
Imports []string
Deps []string
}
const contentTypeJSON = "application/json"
func main() {
http.HandleFunc("/importgraph", func(w http.ResponseWriter, r *http.Request) { importGraph(w, r) })
http.HandleFunc("/", handler)
http.ListenAndServe(":8080", nil)
}
func handler(w http.ResponseWriter, r *http.Request) {
fmt.Println("Inside handler")
fmt.Fprintf(w, "Hello world from my Go program!")
}
func importGraph(w http.ResponseWriter, r *http.Request) {
pack = make(map[string]string)
var t myType
cmd := exec.Command("go", "list", "-json")
stdout, err := cmd.Output()
if err != nil {
println(err.Error())
return
}
var list GoList
err = json.Unmarshal(stdout, &list)
for _, d := range list.Imports {
//get the imports for each of the packages listed by go list -json
t.imports(d)
}
var buff bytes.Buffer
//concatenate the separate json.RawMessages together into json
buff.WriteByte('[')
for i, j := range t.J {
if i != 0 {
buff.WriteByte(',')
}
buff.Write([]byte(j))
}
buff.WriteByte(']')
var buffer bytes.Buffer
if err := json.Compact(&buffer, buff.Bytes()); err != nil {
println(err.Error()) //error message: invalid character ',' looking for beginning of value
return
}
w.Header().Set("Content-Type", contentTypeJSON)
w.Write(buffer.Bytes())
}
func (myObj *myType) imports(pk string) error {
cmd := exec.Command("go", "list", "-json", pk)
stdout, _ := cmd.Output()
pack[pk] = pk
var deplist Import
json.Unmarshal(stdout, &deplist)
var newj json.RawMessage
json.Unmarshal(stdout, &newj)
myObj.J = append(myObj.J, newj)
for _, imp := range deplist.Imports {
if _, ok := pack[imp]; !ok {
myObj.imports(imp) //recursive call to get the imports of the imports etc
}
}
return nil
}
First, as has been commented, are you sure you can't use
the go/build package directly rather than running go list?
I Wouldn't use println (or fmt.Println) inside HTTP handlers. It's much better to use log.Println and/or get the error into the ResponseWriter. Also, it's a good idea to wrap your ListenAndServe call with log.Fatal.
When printing/logging error values you can just use err, no need to have err.Error().
Further, when you actually want to do something more detailed than just reporting/logging the error message you can look at it's type and other info. For example, log.Printf("verbose error info: %#v", err) gives:
&json.SyntaxError{msg:"invalid character ',' looking for beginning of value", Offset:0}
I tried this because I know the json package returns various error types with additional info and I was hoping the offset value would be of help. If it had been then something like this might have been helpful:
if err := json.Compact(…) {
if err != nil {
log.Println("json.Compact:", err)
if serr, ok := err.(*json.SyntaxError); ok {
log.Println("Occurred at offset:", serr.Offset)
// … something to show the data in buff around that offset …
}
}
}
But offset zero isn't helpful :(
So although this doesn't identify you problem hopefully
it can be of some help to your further investigation.
Edit:
So after adding:
log.Println("Write file:", ioutil.WriteFile("data.json", buff.Bytes(), 0600))
to the above error handling block I then ran a JSON validator on the resultant file and it identified this piece:
"XTestImports": [
"io",
"log",
"net"
]
},,{
"Dir": "/usr/local/go/src/mime",
"ImportPath": "mime",
"Name": "mime",
Note the double ,,.
That should tell you whete the error in your code is.
But if not, you need to skip empty entries, either when processing t.J or when you build it. The later is better and just involves:
if len(newj) > 0 {
myObj.J = append(myObj.J, newj)
}
(where btw you don't check for errors from json.Unmarshal so it's not clear if that is supposed to ever be empty or if it's empty due to a preceeding error. Never ignore error returns!)
I also encountered the same error message in a Go program, but the error message was within the HTTP response error, in HTML format when my HTTP response parser expected JSON.
For me, the solution was to change my request to include setting the Content-Type header to application/json. How you do this depends on which http client library you happen to be using; if you have access to the http.Header core type, you can set the header with .Set(...).
I realize the scope of this fix for me may not apply to the original question, but I came here first after googling and thought this would help others, since the message was not particularly obvious at first glance. The hint is that the invalid < character is the first HTML character in the error/response, which is likely the result of the request type not being set to application/json, thus the server responds with a non JSON response.
For me the issue was I was trying to parse the already parsed JSON.
I was also facing this error "invalid character 'N' looking for beginning of value".
This error was coming while "unmarshalling the non-json response into a json". I was expecting a json response, so wrote go code to unmarshal it into a json. But, due to URL change, the response that I was getting was a text ie. "404 Not found" error, which cannot be unmarshalled into a json.
"invalid character 'N' looking for beginning of value"
So, to summarise, this error appears when we are trying to unmarshal a non-json response (text/html/xml) into json.
Reason for this eerie error message is :
// When unmarshaling quoted strings, invalid UTF-8 or
// invalid UTF-16 surrogate pairs are not treated as an error.
// Instead, they are replaced by the Unicode replacement
// character U+FFFD.
https://golang.org/src/encoding/json/decode.go
In my case I saved my json as string then parsed it by :
stringData = JSON.parse(myJsonString)
I also had the same error another time using gin-context-ShouldBind() (https://godoc.org/github.com/gin-gonic/gin#Context.ShouldBind) and mapping my json to go object:
error was because it needs a json as string, so I used : JSON.stringify(jsonObject) when sending my request from front-end part.
And in case someone has the same problem as me, I needed to call JSON.stringify on my post data.
I encountered a similar problem with my error message being:
invalid character 'I' looking for beginning of value
In my case, i was trying to decode BSON using json.Unmarshal. Json doesn't recognize the ISODate type, which caused this error.
I had a similar issue. For me I omitted the first letter of my authorization token. So instead of
"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJlbWFpbCI6InJhcGhhZWxuZ0BlbWFpbC5jb20iLCJleHAiOjE2MTM5NTQzMjB9.yPGC937VNAF8Qg05Z1x3fZ3zu_MUs-cA_Iag5-4RcJE"
I used this
"yJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJlbWFpbCI6InJhcGhhZWxuZ0BlbWFpbC5jb20iLCJleHAiOjE2MTM5NTQzMjB9.yPGC937VNAF8Qg05Z1x3fZ3zu_MUs-cA_Iag5-4RcJE"
I have a zip file stored on Google Drive (it is shared publicly). I want to know how to download it in Golang. This current code just creates a blank file named "file.zip":
package main
import (
"fmt"
"io"
"net/http"
"os"
)
func main() {
url := "https://docs.google.com/uc?export=download&id=0B2Q7X-dUtUBebElySVh1ZS1iaTQ"
fileName := "file.zip"
fmt.Println("Downloading file...")
output, err := os.Create(fileName)
defer output.Close()
response, err := http.Get(url)
if err != nil {
fmt.Println("Error while downloading", url, "-", eerrror)
return
}
defer response.Body.Close()
n, err := io.Copy(output, response.Body)
fmt.Println(n, "bytes downloaded")
}
This appears to be a bug, either with Google drive or with golang, I'm not sure which!
The problem is that the first URL you gave redirects to a second URL which looks something like this
https://doc-00-c8-docs.googleusercontent.com/docs/securesc/ha0ro937gcuc7l7deffksulhg5h7mbp1/8i67l6m6cdojptjuh883mu0qqmtptds1/1376330400000/06448503420061938118/*/0B2Q7X-dUtUBebElySVh1ZS1iaTQ?h=16653014193614665626&e=download
Note the * in the URL which is legal according to this stack overflow question. However it does have a special meaning as a delimeter.
Go fetches the URL with the * encoded as %2A like this
https://doc-00-c8-docs.googleusercontent.com/docs/securesc/ha0ro937gcuc7l7deffksulhg5h7mbp1/8i67l6m6cdojptjuh883mu0qqmtptds1/1376330400000/06448503420061938118/%2A/0B2Q7X-dUtUBebElySVh1ZS1iaTQ?h=16653014193614665626&e=download
Which Google replies "403 Forbidden" to.
Google doesn't seem to be resolving the %2A into a *.
According to this article on wikipedia reserved characters (of which * is one) used in a URI scheme: if it is necessary to use that character for some other purpose, then the character must be percent-encoded.
I'm not enough of an expert on this to say who is right, but since Google wrote both parts of the problem it is definitely their fault somewhere!
Here is the program I was using for testing
I found the solution.
Use: https://googledrive.com/host/ID
Instead of: https://docs.google.com/uc?export=download&id=ID
I'm still investigating on why this is happening, in the meanwhile you can use this workaround:
http://play.golang.org/p/SzGBAiZdGJ
CheckRedirect is called when a redirect happens and you can add an Opaque path to avoid having the URL url-encoded.
Francesc