Of Gravatars and Robohashes

http://www.codingthewheel.com/internet/of-gravatars-and-robohashes

by LiveTheDream • 15 years ago

75 13 15 years ago

codingthewheel.com

bigethan2• 15 years ago

yikes, Gravatar has an open redirect.

http://www.gravatar.com/avatar/8ca7425c8ada807b9bf6934f10d59...

It's a fun trick, but it should't be possible.

grok1fy3• 15 years ago

Gravatar is designed that way so you can use any default image.

The technique is described in the Gravatar docs under "Default Image."

http://en.gravatar.com/site/implement/images/

bigethan2• 15 years ago

Ah. But I'd expect think that they'd limit it to only images, or do some sorta safety checking. I recognize the performance concerns, but it's too easy to add a malware redirect onto their trusted url.

e1ven3• 15 years ago

That is really cool! ;)

I didn't realize that this was a use-case anyone was interested in, but it sort of makes sense. I've added a parameter you can pass to RH.org to deal with the gravatar pull on my side, so you don't have to.

This adds a bit of serverload, since I need to make a bunch of requests, but it's not THAT bad.

http://robohash.org/colin@sq7.org?gravatar=yes

If you pass gravatar=yes, it will make a pull to the gravatar URL for that address. If something exists there that isn't the default, it will issue a 301 over to the site.

Otherwise, it will return the robohash you requested. It also passes the size param over to Gravatar, just to be nice ;)

grok1fy3• 15 years ago

Gravatar uses hashes for privacy so the email addresses themselves do not have to be transmitted.

To maintain email privacy, you could use a straight pass-through when using Gravatar. In this case, your URL could look like:

http://robohash.org/620050a4db5104bae758cd75171d64ca?gravata...

e1ven3• 15 years ago

Good idea!

I've added this.

Try - http://robohash.org/620050a4db5104bae758cd75171d64ca?gravata...

erikig• 15 years ago

Very nice, I was planning to implement a similar thing with for 'anonymous' ip-based human readable usernames to identify users without forcing them to create profiles.

An excellent bonus - my robohash looks exactly like Bender from Futurama :^)

anoopks• 15 years ago

How will you handle thousands of users behind a corporate firewall?

unfletch• 15 years ago

Nice work, but the "they look like they were drawn by programmers" comment makes me think you missed the point of Gravatar's specific default avatars.

They're intentionally ugly. The theory is that an ugly default avatar makes the user more likely to upload their own image.

codingthebeach• 15 years ago

Interesting point. Wavatars are Shamus Young's original work.[1] Identicons[2] and monsterids[3] are Scott Sherill-Mix's work. I don't think those guys were shooting for "ugly", but I agree an ugly or nondescript avatar could incentivize users to upload a custom one. And that may have played into Gravatar's decision to support these avatar types.

[1] http://www.shamusyoung.com/twentysidedtale/?p=1462

[2] http://scott.sherrillmix.com/blog/blogger/wp_identicon/

[3] http://scott.sherrillmix.com/blog/blogger/wp_monsterid/

grok1fy3• 15 years ago

Minor correction: Identicons were created by Don Park who open sourced a Java implementation. Scott adapted it for WordPress and gives credit to Don credit for the idea in your link[2]:

"A couple weeks ago I made a WordPress plugin to generate unique monsters for each commenter. Don Park came up with the original idea for representing users with geometric shapes. Since I already had the framework in place I thought I’d make a WordPress plugin for the original geometric Identicons."

nirvana• 15 years ago

I'm curious how many variations robohash uses. It seems either you've got a very wide variety of custom graphics elements, or only a few elements and have to draw a very wide number of images to fit in them.

Each two digits of hex is 255, and I count 16 pairs, but can think of only 8 elements in the photos (eyes, ears, nose, mouth, head, body, arms, background).

If it's those 8 elements and they're derived from four digits in the hash, then you need 65,535 or so different ears.

I'm guessing the solution to this is to reduce the hash further... so you get more repetition where two texts produce the same robot, but apparently they've not made it too bad.

How far did robohash reduce it? Or how far should one reduce it? How many images does a robohash art set have?

e1ven3• 15 years ago

It depends on which set you use.

There are three sets-

The default set has 10 base colors, 10 base faces, 10 Bodies, 10 Eyes, 10 Accessories, 10 Mouths.

There are then 2 sets of 10 backgrounds.

So 3(10^6)(210) ~= 60,000,000

Of Gravatars and Robohashes

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