# Inspect\_message for Motoko **URL:** \ **Category:** Language Support\ **Tags:** Motoko\ **Created:** [January 22, 2022, 4:21pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430 "2022-01-22T16:21:39Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Motokoder](https://avatars.discourse-cdn.com/v4/letter/m/e47c2d/32.png) [@Motokoder](https://forum.dfinity.org/u/Motokoder)\ **Post date:** [January 22, 2022, 4:21pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/1 "2022-01-22T16:21:39Z")
Is the _inspect\_message_ function planned for Motoko in the near future? Also, will inspecting and discarding an ingress message with a large payload prevent the canister from being charged cycles, other than the cost of cycles for the _inspect\_message_ function itself? Lastly, even if Motoko gets _inspect\_message_, how can a canister defend against a hacker deploying another canister and sending large inter-canister payloads to a function in a constant loop? I imagine the function logic could throttle or block repeated requests from the same principal (saving storage), but afaik, the cycles will still get drained. Thanks. ---
**Author:** ![skilesare](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/skilesare/32/5609_2.png) [@skilesare](https://forum.dfinity.org/u/skilesare)\ **Post date:** [March 4, 2022, 4:05am UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/2 "2022-03-04T04:05:30Z")
Bump. What is the status of inspect\_message for motoko? ---
**Author:** ![claudio](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/claudio/32/322_2.png) [@claudio](https://forum.dfinity.org/u/claudio)\ **Post date:** [March 9, 2022, 6:21pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/3 "2022-03-09T18:21:45Z")
Stalled in bikeshedding [Feature: support system method `inspect-message` · Issue #2528 · dfinity/motoko · GitHub](https://github.com/dfinity/motoko/issues/2528) ---
**Author:** ![jzxchiang](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/jzxchiang/32/2592_2.png) [@jzxchiang](https://forum.dfinity.org/u/jzxchiang)\ **Post date:** [April 18, 2022, 3:41am UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/4 "2022-04-18T03:41:47Z")
Will this be taken up again soon? I think inspect\_message can be really valuable to use for early authentication in order to prevent cycle drainage attacks. ---
**Author:** ![claudio](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/claudio/32/322_2.png) [@claudio](https://forum.dfinity.org/u/claudio)\ **Post date:** [April 23, 2022, 7:31pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/5 "2022-04-23T19:31:12Z")
I may have a go at this this week. If you have an strong opinion about the proposals in ([Feature: support system method `inspect-message` · Issue #2528 · dfinity/motoko · GitHub](https://github.com/dfinity/motoko/issues/2528)) do chime in. ---
**Author:** ![Motokoder](https://avatars.discourse-cdn.com/v4/letter/m/e47c2d/32.png) [@Motokoder](https://forum.dfinity.org/u/Motokoder)\ **Post date:** [April 23, 2022, 8:00pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/6 "2022-04-23T20:00:47Z")
I have a strong opinion that it’s needed. Without the ability to intercept messages, any canister written with Motoko is vulnerable to a cycle drain attack. ---
**Author:** ![lastmjs](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/lastmjs/32/3406_2.png) [@lastmjs](https://forum.dfinity.org/u/lastmjs)\ **Post date:** [June 24, 2022, 9:35pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/7 "2022-06-24T21:35:49Z")
Is this live in Motoko? ---
**Author:** ![claudio](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/claudio/32/322_2.png) [@claudio](https://forum.dfinity.org/u/claudio)\ **Post date:** [July 5, 2022, 7:29am UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/8 "2022-07-05T07:29:34Z")
Yes, it should be. Try it from the playground. > **[Message inspection | Internet Computer Home](https://internetcomputer.org/docs/current/developer-docs/build/languages/motoko/message-inspection/)** > > On the Internet Computer, a canister can selectively inspect and accept or decline ingress messages submitted through the HTTP interface: ---
**Author:** ![Motokoder](https://avatars.discourse-cdn.com/v4/letter/m/e47c2d/32.png) [@Motokoder](https://forum.dfinity.org/u/Motokoder)\ **Post date:** [July 6, 2022, 2:13pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/9 "2022-07-06T14:13:07Z")
Thank you Claudio!!! ---
**Author:** ![icme](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/icme/32/4327_2.png) [@icme](https://forum.dfinity.org/u/icme)\ **Post date:** [November 16, 2022, 5:54am UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/10 "2022-11-16T05:54:41Z")
I’m currently unable to restrict query or shared query functions with `inspect_message` (update calls work fine). I took the example from the documentation and put it on the playground. [https://m7sm4-2iaaa-aaaab-qabra-cai.raw.ic0.app/?tag=4144018877](https://m7sm4-2iaaa-aaaab-qabra-cai.raw.ic0.app/?tag=4144018877) ---
**Author:** ![claudio](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/claudio/32/322_2.png) [@claudio](https://forum.dfinity.org/u/claudio)\ **Post date:** [November 17, 2022, 4:50pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/11 "2022-11-17T16:50:59Z")
Its probably not kicking in for queries because the playground issues them as query, not update, ingress messages. But I’m not sure. ---
**Author:** ![chenyan](https://avatars.discourse-cdn.com/v4/letter/c/35a633/32.png) [@chenyan](https://forum.dfinity.org/u/chenyan)\ **Post date:** [November 18, 2022, 7:32pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/12 "2022-11-18T19:32:11Z")
`inspect_message` doesn’t apply to query calls. See the interface spec: [The Internet Computer Interface Specification | Internet Computer Home](https://internetcomputer.org/docs/current/references/ic-interface-spec#system-api-inspect-message) ---
**Author:** ![icme](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/icme/32/4327_2.png) [@icme](https://forum.dfinity.org/u/icme)\ **Post date:** [November 18, 2022, 7:52pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/13 "2022-11-18T19:52:28Z")
Got it, thanks! @claudio then the docs [here](https://internetcomputer.org/docs/current/developer-docs/build/cdks/motoko-dfinity/message-inspection/#example) should remove the query call from the `inspect_message` call? Does it make sense for query calls to be included in the `msg` arg since they won’t be blocked regardless of the boolean returned? ---
**Author:** ![claudio](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/claudio/32/322_2.png) [@claudio](https://forum.dfinity.org/u/claudio)\ **Post date:** [November 24, 2022, 6:15pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/14 "2022-11-24T18:15:55Z")
Confusingly, a `shared query` function _can_ be called using a regular HTTP call to obtain a certified response: this is why the variant type also includes `shared query` functions. You would probably need to use dfx with a manually issued, certified (not plain) query to observe the filtering. ---
**Author:** ![skilesare](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/skilesare/32/5609_2.png) [@skilesare](https://forum.dfinity.org/u/skilesare)\ **Post date:** [November 24, 2022, 9:48pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/15 "2022-11-24T21:48:16Z")
If you are trying to restrict something you could force an update by using the http\_upgrade header which would force an update. ---
**Author:** ![icme](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/icme/32/4327_2.png) [@icme](https://forum.dfinity.org/u/icme)\ **Post date:** [November 25, 2022, 12:13am UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/16 "2022-11-25T00:13:38Z")
A “nice-to-have” would be if inspect\_message could apply to query calls as well. Any idea how difficult this change would be? ---
**Author:** ![chenyan](https://avatars.discourse-cdn.com/v4/letter/c/35a633/32.png) [@chenyan](https://forum.dfinity.org/u/chenyan)\ **Post date:** [November 25, 2022, 4:22am UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/17 "2022-11-25T04:22:49Z")
Okay, I’m confused. You mean I can call the `shared query` function as an update method, and this update call can be filtered by `inspect_messge`? Is this mentioned in the spec? ---
**Author:** ![timo](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/timo/32/5543_2.png) [@timo](https://forum.dfinity.org/u/timo)\ **Post date:** [November 25, 2022, 6:43am UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/18 "2022-11-25T06:43:00Z")
> [@icme](#): > > A “nice-to-have” would be if inspect\_message could apply to query calls as well. Any idea how difficult this change would be? I understood that inspect\_message is there so that you can run some code on one replica first before it goes through the expensive process of being run on all replicas. So for a query call (that is called as a query call) you can just put the filtering code directly into the query function. You don’t need inspect\_message to achieve the same result. ---
**Author:** ![claudio](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.dfinity.org/claudio/32/322_2.png) [@claudio](https://forum.dfinity.org/u/claudio)\ **Post date:** [November 30, 2022, 7:16pm UTC](https://forum.dfinity.org/t/inspect-message-for-motoko/10430/19 "2022-11-30T19:16:43Z")
> [@chenyan](#): > > Okay, I’m confused. You mean I can call the `shared query` function as an update method, and this update call can be filtered by `inspect_messge`? Is this mentioned in the spec? Yes, I believe so, if you squint at the spec. The calls goes through concensus, state changes are transient, and filtering is applied. IIRC.