Show HN: HTTP Mock – Intercept, debug and mock HTTP(S) with zero setup

by pimterry • 7 years ago

341 84 7 years ago

pimterry23• 7 years ago

Hey HN! I've been building this for a while, but up until now it's been a read-only HTTP debugging tool, and today's my first foray into proper mocking, which opens up a whole new world of fun (and practical use cases).

Let me know what you think :-)

mateuszf2• 7 years ago

Didn't try it yet but the promise is amazing.

pault2• 7 years ago

I hope this works out! Using fiddler us such a frustrating experience. The documentation is practically non existent and the ux is atrocious, and as far as I can tell the closest thing to a manual is a paid ebook by the developer (I was so pissed when I discovered this). I would be very happy to have an open source alternative!

pimterry23• 7 years ago

Me too :-). I built this myself in large part because of frustrations with Fiddler. It was an amazing tool at the time, but it hasn't aged well imo...

Hopefully this is your open source alternative - give it a go, let me know if there's something Fiddler does for you that HTTP Toolkit doesn't!

altano2• 7 years ago

If you think Fiddler sucks get a Mac and try using the tools available there like Charles Proxy. Ugh.

jmkni2• 7 years ago

I don't mind Fiddler, and $15 dollars for a book on a free, incredibly powerful, tool is a bargain IMHO.

RMPR• 7 years ago

It may be interesting to have a rpm package

mariocesar• 7 years ago

There are full opensource alternative for this? I like the product, I'm testing it right now. But I'm curious if there is a way to accomplish something like this with existing opensource tools or a similar full opensource project.

mateuszf2• 7 years ago

I think you can use for example mitmproxy for this though with more setup

LongBallLary• 7 years ago

It is 100% open source according to their website (in the footer). https://github.com/httptoolkit

reffaelwallen• 7 years ago

I think it is opensource no?

https://github.com/httptoolkit

Nodraak• 7 years ago

Would not be able to exactly explain the features and differences, but https://mitmproxy.org/ is a similar project you might be interested in.

ORioN63• 7 years ago

mitmproxy is indeed a similar project. It offers a dashboard similar to devtools (no modifying in there though).

You can, however, write small python scripts that have read-write access to the http flow (request and response objects).

I guess it's a more low level tool, because it doesn't provide mocking and other helpful tools out of the box.

donaldihunter• 7 years ago

Yep, mitmproxy is my go-to tool, but HTTP Mock maybe wins for zero-setup convenience.

pimterry23• 7 years ago

HTTP Toolkit is fully open source, primarily AGPL: https://github.com/httptoolkit/. That includes the Pro version too - it's not open core, it's just open source all the way down.

There are other tools that exist anyway, but all the big ones (Fiddler & Charles, for Windows & OSX respectively) are very much closed source. The other similar open source competitor I'm familiar with is James Proxy (https://github.com/james-proxy/james) but that's now effectively unmaintained.

For comparison, using the internals of Fiddler by itself would cost $2,999 per application per year (https://www.telerik.com/purchase/fiddlercore). The standalone internals of HTTP Toolkit OTOH are on GitHub: https://github.com/httptoolkit/mockttp.

xyzzy_plugh• 7 years ago

The parent was likely referring to AGPL, a somewhat-encumbered copyleft license, which most folks working in proprietary software are hesitant to touch. They are probably looking for a non-copyleft license.

Though, as a development tool, I don't see any issues using AGPL software.

insomniacity2• 7 years ago

I've not looked at the code, but wouldn't it be possible to patch this and enable Pro mode without paying?

Morally bad and ultimately self-defeating, but I'm guessing legally fine?

sebazzz3• 7 years ago

How does this compare Fiddler?

pimterry23• 7 years ago

It has all the same core functionality, plus:

- It's open-source

- It's cross-platform

- It can do all the interception setup for you, for a single specific target. Fiddler et al set the system proxy, so there's a lot of other traffic going on, and you then need to make applications trust the certificate manually too. Notably some apps (like Node) ignore the system proxy settings entirely, which means you need code changes. HTTP Toolkit does some clever injection, and skips all of that.

- Nice & modern UI

- Built in docs for all standard HTTP status codes/headers/methods/etc

- The Pro features: validation & inline docs from 1400+ API specifications, testing & comparison of compression options, explanations for how your response will be cached & why (and warnings).

I keep meaning to do a proper comparison page (any day now), but that's the gist.

nachi• 7 years ago

What about intercepting requests from other devices on the same network? Fiddler and Charles both let you set a proxy on Android/iOS devices pointing to your instance.

sebazzz3• 7 years ago

Fiddler is a bit of an ugly duck, and you even have to give your e-mail address away to Telerik. However, it does have scripting ability and supports extensions and one can be very powerful in it if you know what to look for.

I actually use extension functionality to extend Fiddler a bit to emulate our internal authenticating proxies we have at work (like PingFederation).

barberousse• 7 years ago

Am getting too many redirects opening that link

pimterry23• 7 years ago

Huh, that shouldn't happen! What browser & OS are you using?

kevinday2• 7 years ago

I'm getting the same on Chrome/Mac. Requesting /mock/ just 301's me back to /mock/

https://pastebin.com/vmgSU6nj

swiley• 7 years ago

THIS would have been nice to have at the beginning of the summer.

The tests I wrote tested the boundary between my code and the HTTP library but the API I was writing against wasn't particularly well behaved and so that wasn't quite enough.

meritt• 7 years ago

How is this achieving https interception with zero setup? Does that not require a system-level root CA to be installed and trusted?

pimterry23• 7 years ago

Does that not require a system-level root CA to be installed and trusted?

No, happily :-)

The trick is that it starts the application to be intercepted for you, so it can control it a little. It then does some magic to get that specific instance of the application to trust the certificate. There's a lot going on there, but as an example: Chrome has a --ignore-certificate-errors-spki-list to inject the hashes of extra CAs that can be trusted in this specific Chrome instance. When HTTP Toolkit starts a Chrome process, it adds that command line option, with the hash of your locally generated CA.

There's nothing here with a lasting effect, and other running apps on your machine won't trust HTTP Toolkit unless you specifically configure them to. Only the processes spawned by HTTP Toolkit trust your CA, which avoids a lot of the downside of other similar tools like this.

debatem13• 7 years ago

So, I'm confused. Does this work on a set of programs where you know eg the right command line parameters to give them or on all programs?

For example, let's say I have a program which uses the openssl API to set a custom trust store. Do you mess with openssl to make sure your cert is in there, or will this break?

miles• 7 years ago

Netripper[0] can also intercept HTTPS with zero setup via DLL injection. I cobbled together a simple guide[1] on its use, though for Chrome, signature changes have made it a bit more challenging[2].

[0] https://github.com/NytroRST/NetRipper

[1] https://tinyapps.org/blog/201508150700_sniffing_encrypted_tr...

[2] https://github.com/NytroRST/NetRipper/issues/21

hartator2• 7 years ago

Love it. We definitely need a fiddler in macosx.

gmanley• 7 years ago

Charles is pretty good, though it’s paid. It’s definitely nice to have an opensource tool, though.

hartator2• 7 years ago

Charles is okay. But when you have been used to Fiddler is hard to go back.

chrismatheson2• 7 years ago

Is this something that could be used in a CI pipeline as well?

pimterry23• 7 years ago

As a UI desktop app, not really, although it depends what you're trying to do. However, the internals are all open-source too, so you can use them standalone and automate HTTP & HTTPS with that. Take a look at https://github.com/httptoolkit/mockttp

chrismatheson2• 7 years ago

I think (maybe postman) had a nice gui, and then the same mocks could be loaded up as part of a test. I was thinking more along the lines of how the application actually inspects network traffic, is that something that could be setup & torn down within a unprivileged docker container for example?

cdeutsch• 7 years ago

You could try a cloud based solution like https://curlhub.io/

dessant2• 7 years ago

Is intercepting Android traffic planned?

pimterry23• 7 years ago

Yes, definitely! You can follow progress by subscribing to this GH issue: https://github.com/httptoolkit/feedback/issues/10 (or signing up to the general HTTP Toolkit mailing list ofc).

In the meantime, it's quite possible to intercept Android traffic, it's just that you'll have to do the proxy & certificate setup yourself.

dessant2• 7 years ago

That's great, thanks for the link! In recent Android versions it has become difficult to inspect the traffic precisely because certificates installed by users are no longer trusted, so one has to either root the phone or modify the apk.

Do you plan to automate app repackaging with the needed changes, or is there a better method for apps to trust local certificates?

mcx• 7 years ago

Would be cool to have something like this for debugging outgoing container traffic in Kubernetes.

pimterry23• 7 years ago

Docker is on the list: https://github.com/httptoolkit/feedback/issues/1 (you can subscribe to that for updates). Would that work for your setup?

guardiangod• 7 years ago

Thanks for the tool.

Is it possible for HTTP Mock to dump both the entire SSL session traffic, and the decrypted HTTP traffic (with fake tcp headers), to pcaps for future analysis?

jordache• 7 years ago

why do I need to create an account for this?

gawd... I just need a Fiddler in macOS... one can't really improve what Fiddler provides.

pimterry23• 7 years ago

You don't need to create an account for this! Click download, use the app, it's fine.

You can provide your email after download if you want updates from the mailing list (or you can not), and you can click 'Get Pro' somewhere and provide your email if you want a paid Pro account. The core app will give you pretty much everything Fiddler does though, on Mac, and doesn't require your email or anything else.

bdcravens• 7 years ago

I understand why you're doing it, but the download link redirecting me to an email capture page is quite jarring. If your download link is at the top of your homepage, and there's more product details below that link, it's pretty typical to hit download and assume it's a normal download link while you read the rest of the page. An easily dismissible modal would work better (or put an email capture in your app on first-run)

pimterry23• 7 years ago

Hmm, interesting. I really just did it without much thought, I didn't think it was particularly unusual behaviour.

That said, this completely makes sense, I'm definitely going to look at that. I could fairly easily swap the 'sign up for updates' in directly in place of the download button when that's clicked I think, which would avoid the extra page and the modal all together, make everything much nicer, and still give keen users a clear opportunity to properly follow the project.

Thanks! Great point.

gatherhunterer• 7 years ago

I don't see too much of a problem, just that if the download link does not come up right away (this could be caused by a user's browser settings or connection speed, which are beyond your control) it looks like they have been taken to a "Here, have some spam instead" page. I would just switch the position and styling of "Sign up for updates" and "You are now downloading..." so that confirming the download request is the primary message on the screen. You could also ask a user to wait three seconds and make them look at your (now less prominent) appeal to sign-up for emails while they do so.

The project looks very nice and I do a lot of HTTP work so I will try it out today. Good work!

ElijahLynn6• 7 years ago

+1 for easy access download without forcing an email submission.

update: K, I had gotten side tracked and forgot that it already downloaded and left me on the email submission page. User error. Downloads fine without email.

viana007• 7 years ago

For this type of HTTP intercept I like to use Fiddler and Charles.

jame_bkk2• 7 years ago

How does HTTP Mock compare with Proxymam.io? Your tool is promising with zero-setup, but it works with different macOS app, doesn't it?

I would try it tmr.

nghiatran_feels• 7 years ago

The first noticeable feature is that HTTP Mock is cross-platform and Proxyman is exclusively built on macOS.

I'm not sure how zero-setup works, but it's cool feature indeed. I was frustrated to setup those certificate on Fiddler. I suppose that Fiddler tends to expert users, not me.

ElijahLynn6• 7 years ago

Arch AUR package here everyone > https://aur.archlinux.org/packages/httptoolkit/

`yay -S httptoolkit`

AUR is 0.1.13 and latest is 0.1.14 fwiw.

ElijahLynn6• 7 years ago

WOW. Just WOW. Easiest intercepter I have EVER used. (Charles, Fiddler, MITMProxy). After install I was able to edit requests and responses with the MOCK rules in no time.

The language was confusing but I got through it and WOW.

Nice job on the UI too, Linux UI's are hit or miss and HTTP Toolkit's is pleasant!

pimterry23• 7 years ago

Haha, thanks! Glad you like it.

When you say 'the language was confusing' though, what do you mean? I should fix that.

ElijahLynn6• 7 years ago

Alrighty, after tinkering yesterday an opportunity came up to use this for real work! And helped us mock testing for a bad JSON response we are seeing on a remote server, but mocked it locally for better error logging. (gave shoutout to HTTP Toolkit here > https://github.com/department-of-veterans-affairs/vets-websi...)

This just earned a subscription, will get it processed soon! Thanks again, a breeze to use!

ElijahLynn6• 7 years ago

Totally nice side effect. Since this launches "fresh Chrome/Firefox". I can use it to read all these paid news sites that track how many "free articles" I have and don't have to worry about resetting all my cookies. Just launch HTTP Toolkit then Fresh Firefox/Chrome, paste link and done.

meowface• 7 years ago

You can also open the dev console and click "Clear site data". It won't evade complex tracking/fingerprinting techniques, but I don't think paywall sites use those to enforce the paywall (yet...).

kaushikt• 7 years ago

Is netflix's PollyJS also trying to solve this? https://netflix.github.io/pollyjs/#/

Show HN: HTTP Mock – Intercept, debug and mock HTTP(S) with zero setup

Related Stories