Why stream error: stream ID 1; CANCEL; received from peer?

Few days ago my GMC Map proxy stopped working.
This is the service I made few years ago to fasten the data loading of my app.
The gmcparse program sends an HTTP GET request and matches a bunch of regexes on the response to extract useful data for the app.
All I know from the pod log is that the server is resetting connections from my client.

From gmcparse:

/ $ gmcparse 
main.go:48: INFO: Fetching https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0
main.go:52: Get "https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0": stream error: stream ID 1; CANCEL; received from peer

Request to the same URL from the same IP: no problems.

[fmac@kube1 ~]$ curl -I 'https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0'
HTTP/2 200 
cache-control: private
content-length: 575571
content-type: text/html
server: Microsoft-IIS/10.0
set-cookie: ASPSESSIONIDQGTTSSRD=JKEEPBDBOEIKLDFLAIPPNJAC; secure; path=/
x-powered-by: ASP.NET
x-powered-by-plesk: PleskWin
date: Mon, 31 Mar 2025 21:36:24 GMT

OK, they’re not blocking my IP.

Let me try locally with the same image.

docker pull camuffo/gmcmap-parser:latest
[I] fmac@absinthe ~ (main) [1]> docker run --rm -it camuffo/gmcmap-parser:latest gmcparse
main.go:48: INFO: Fetching https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0
main.go:52: Get "https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0": stream error: stream ID 1; CANCEL; received from peer

Same issue.

Does rebuilding the program with the latest Go fix it?

[I] fmac@absinthe ~/s/gqelectronics-gmcmap-parser (main)> go build main.go
[I] fmac@absinthe ~/s/gqelectronics-gmcmap-parser (main)> ./main
main.go:48: INFO: Fetching https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0
main.go:52: Get "https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0": stream error: stream ID 1; CANCEL; received from peer

No.

I wanna see what’s going on.

[I] fmac@absinthe ~ (main) [1]> yay -S zaproxy
[I] fmac@absinthe ~ (main)> export _JAVA_OPTIONS='-Dsun.java2d.uiScale=2.5' # (java lol)
[I] fmac@absinthe ~ (main)> zaproxy 

doas mv zap_root_ca.cer /usr/share/ca-certificates/trust-source/anchors/
doas update-ca-trust

[I] fmac@absinthe ~/s/gqelectronics-gmcmap-parser (main)> export http_proxy=127.0.0.1:8080
[I] fmac@absinthe ~/s/gqelectronics-gmcmap-parser (main)> export https_proxy=127.0.0.1:8080
[I] fmac@absinthe ~/s/gqelectronics-gmcmap-parser (main)> ./main
main.go:48: INFO: Fetching https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0
main.go:68: INFO: Deduplicated 0 lines
main.go:70: INFO: Parsing 5102 bytes, 0 lines (\r)
main.go:172: INFO: Parsed 0 mearuments
[]

On ZAP:

Nothing unexpected here. The Java client is getting a reset as well. Not a problem with the Go client.

This is when my fear of GQ Electronics having done something sad started to grow over the expectations.

Please, don’t tell me you banned the Go user agent string.

And apparently, yes, they did.
This is very sad.
I don’t wanna think they banned this UA string because of my service. Probably they were bothered by other bots. I might end up asking them the reason behind this in the forum. In any case, since they were not so nice to whitelist my IP, from now on I’ll present myself with the motherfucking Chrome user agent string.

Let me patch the program to support customizing the UA string.

--- a/main.go
+++ b/main.go
@@ -30,14 +30,15 @@ type Measurement struct {
 }
 
 var url string
+var uaString string
 
 func init() {
        const (
                defaultUrl = "https://gmcmap.com/ajaxm.asp?OffSet=0&Limit=1000000&dataRange=1&timeZone=0"
-               usage      = "URL"
        )
-       flag.StringVar(&url, "url", defaultUrl, usage)
-       flag.StringVar(&url, "u", defaultUrl, usage+" (shorthand)")
+       flag.StringVar(&uaString, "useragent", "", "User-agent string")
+       flag.StringVar(&url, "url", defaultUrl, "URL")
+       flag.StringVar(&url, "u", defaultUrl, "URL (shorthand)")
 }
 
 func main() {
@@ -47,7 +48,22 @@ func main() {
 
        errLog.Printf("INFO: Fetching %v", url)
 
-       resp, err := http.Get(url)
+       client := &http.Client{
+               Transport: &http.Transport{
+                       Proxy: http.ProxyFromEnvironment,
+               },
+       }
+
+       req, err := http.NewRequest("GET", url, nil)
+       if err != nil {
+               errLog.Fatalf("ERROR: creating HTTP request: %v", err)
+       }
+
+       if uaString != "" {
+               req.Header.Set("User-Agent", uaString)
+       }
+
+       resp, err := client.Do(req)
        if err != nil {
                errLog.Fatal(err)
        }

commit

Let’s try this.

./main -useragent 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36'

OK. I’ll fix the Dockerfile to support this and roll out.

This was really a bad surprise from GQ Electronics, since they manufactured two of my beloved dosimeters.