Add template support #285
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -8,6 +8,7 @@ import ( | |
| "net/http" | ||
| "os" | ||
| "strings" | ||
| "text/template" | ||
| "time" | ||
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| "github.com/gorilla/mux" | ||
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@@ -32,33 +33,59 @@ func NewHTTPSrv(stats *base.StatsRegistry, debugConfig *base.ChatDebugOutputConf | |
| return h | ||
| } | ||
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| func injectTemplateVars(webhookName, webhookMethod, template string) string { | ||
| return fmt.Sprintf("{{$webhookName := %q}}{{$webhookMethod := %q}} %s", webhookName, webhookMethod, template) | ||
| } | ||
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| func (h *HTTPSrv) getMessage(r *http.Request, hook webhook) (string, error) { | ||
| if r.Method == http.MethodGet && len(hook.template) == 0 { | ||
| j, err := json.Marshal(r.URL.Query()) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
| return string(j), nil | ||
| } | ||
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| if r.Method == http.MethodPost && len(hook.template) == 0 { | ||
| defer r.Body.Close() | ||
| body, err := ioutil.ReadAll(r.Body) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
| return string(body), nil | ||
| } | ||
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| tWithVars := injectTemplateVars(hook.name, r.Method, hook.template) | ||
| t, err := template.New("").Parse(tWithVars) | ||
| if err != nil { | ||
| return "`Error: failed to parse template: " + err.Error() + "`", nil | ||
| } | ||
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| if r.Method == http.MethodGet { | ||
| buf := new(bytes.Buffer) | ||
| if err := t.Execute(buf, r.URL.Query()); err == nil { | ||
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Contributor
There was a problem hiding this comment. perhaps the template population should be timeboxed (context.WithTimeout) (and in a separate goroutine) so a malicious template (infinite loop) doesn't halt the bot
Author
There was a problem hiding this comment. i've spent some time looking into this and thinking about how it would be done and i'm struggling to think of how we would cancel the i also did some tests to see if it's possible to create some kind of malicious template with an infinite loop, and it turns out that if you create a template that ranges over nothing, like if you still think we should timebox this, i'd be interested in your thoughts about how to kill that
Contributor
There was a problem hiding this comment. Would a recursive template like this be possible? https://play.golang.org/p/uMN1IsGB4xl It might be useful to look at this issue golang/go#31107
Contributor
There was a problem hiding this comment. I realized that my playground example might not be super realistic since playground has some pretty strict timing & memory restrictions. It seems like Execute gives up at some depth (100000 from the source). However, I came up with something that gets killed by the linux OOM killer when writing to a
Author
There was a problem hiding this comment.
i tried this on an instance of the bot that i'm currently running, and it did not work. i tried it exactly as you have it here, which takes no input from any fields on the webhook, and i also modified it a bit to take a but this was a really cool approach. i'm kind of curious why this works in the playground but not the bot. out of curiosity i also put your example in a file and compiled it and it runs in under a second before exiting, and it prints out a bunch of the
thank you for this! i skimmed it a but just now but will have to read through it a bit when i have more time. it looks like there may be some good ideas in there that i can use.
perhaps this explains the behavior i mentioned abovened above
i'll look into this, thanks for the suggestion. i'd be interested to see what you came up with. |
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| return buf.String(), nil | ||
| } | ||
| } | ||
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| if r.Method == http.MethodPost { | ||
| defer r.Body.Close() | ||
| body, err := ioutil.ReadAll(r.Body) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
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| m := map[string]interface{}{} | ||
| err = json.Unmarshal(body, &m) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
| buf := new(bytes.Buffer) | ||
| if err := t.Execute(buf, m); err == nil && len(buf.String()) > 0 { | ||
| return buf.String(), nil | ||
| } | ||
| } | ||
| return "", nil | ||
| } | ||
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| func (h *HTTPSrv) handleHook(w http.ResponseWriter, r *http.Request) { | ||
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@@ -71,15 +98,19 @@ func (h *HTTPSrv) handleHook(w http.ResponseWriter, r *http.Request) { | |
| w.WriteHeader(http.StatusNotFound) | ||
| return | ||
| } | ||
| msg, err := h.getMessage(r, hook) | ||
| if err != nil { | ||
| h.Stats.Count("handle - no message") | ||
| h.Errorf("handleHook: failed to find message: %s", err) | ||
| w.WriteHeader(http.StatusBadRequest) | ||
| return | ||
| } | ||
| if strings.TrimSpace(msg) == "" { | ||
| h.Stats.Count("handle - empty msg") | ||
| return | ||
| } | ||
| h.Stats.Count("handle - success") | ||
| if _, err := h.Config().KBC.SendMessageByConvID(hook.convID, " %s", msg); err != nil { | ||
| if base.IsDeletedConvError(err) { | ||
| h.Debug("ChatEcho: failed to send echo message: %s", err) | ||
| return | ||
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