Some Pixels » Think

502 Proxy Error / Uploading from Apache (mod_proxy) to Tomcat 7

André Gil — Sat, 15 Dec 2012 02:43:19 +0000

I’ve been working on a product lately where we need a reverse proxy from the Apache, serving our static content, to the Tomcat 7 where our API is. We’re using mod_proxy
to do the job and everything is hosted on Amazon’s EC2.

Everything was working perfectly, but sometime ago we’ve started to see some errors, when uploading big files, like this:

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Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request POST /app/api/upload.

Reason: Error reading from remote server

Apache/2.2.22 (Amazon) Server at our_app_server.com Port 443

We started looking for solutions to this problem and tried a lot of things, like configuring the timeout on Apache’s httpd.conf:

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# Configuring the timeout
Timeout 2400
ProxyTimeout 2400

# Configuring the reverse proxy
ProxyPass /app http://localhost:8080/app
ProxyPassReverse /app http://localhost:8080/app

After we’ve changed the timeout, it got a little better, but didn’t solve the problem completely. So, after a lot more googling, we found out that this error on Apache’s log:

1	(103)Software caused connection abort: proxy: pass request body failed

is caused by a malformed server response and, to ignore it, we could set this option on our httpd.conf:

1	ProxyBadHeader Ignore

After this change, it finally revealed to us the real problem:

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org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.web.multipart.MultipartException: Could not parse multipart servlet request; nested exception is org.apache.commons.fileupload.FileUploadBase$IOFileUploadException: Processing of multipart/form-data request failed. Read timed out
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:894)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:312)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)
org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:324)

We started looking for the solution again and found a interesting Tomcat setting called disableUploadTimeout. People usually think you should set it as true, since the name is a little confusing, but if you read the docs you’ll see that the default is true and you have to set it false if you want the timeout to be longer for uploads. Now this is my Connector at Tomcat’s conf/server.xml file:

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connectionTimeout="60000" disableUploadTimeout="false"
redirectPort="8443" />

If you’re having the same problem, I hope this post has saved your life… ;]

Stop accidentally quitting Apps (CMD+Q)

André Gil — Tue, 06 Nov 2012 19:09:16 +0000

Have you ever accidentally hit CMD+Q, instead of CMD+W, on your Mac and closed the entire App when you really wanted to close just one tab? I know you did!

So now I’ll teach you how to prevent that! Just follow these steps and thank me later…

Open “System Preferences”
Select “Keyboard”
And “Keyboard Shortcuts”
Now click at “Application Shurtcuts” to add a new custom shortcut
Click on the “plus” sign
Select the App you want to “protect”
On “Menu Title”, enter the exact label from the menu option to exit the app you selected. (eg. On Google Chrome, it’s “Quit Google Chrome”. In some other apps, it’s just “Quit”)
On “Keyboard Shurtcut”, type something safe. Like CONTROL + COMMAND + Q

You can use this tip to change any other shortcut or even add shortcuts to menu options without one previously assigned.

Xiki: A shell console on steroids

André Gil — Fri, 14 Sep 2012 18:51:59 +0000

Wow… I don’t even have words to describe Xiki. Just watch the introductory video, it’s amazing!!

o_O

Disable Auto Correct and Auto Capitalize on mobile inputs

André Gil — Wed, 12 Sep 2012 03:42:10 +0000

When you’re developing web apps for mobile devices, you usually don’t want the iOS/Android to auto correct or auto capitalize all your inputs, like user name or e-mail. To disable these features, you can use:

1	<input type="text" autocorrect="off" autocapitalize="off" autocomplete="off" />

The autocorrect and autocapitalize attributes works on the iPhone or the iPad, and the autocomplete is for any device running Android.

Escape any String to be “Regular-Expression-safe”

André Gil — Tue, 11 Sep 2012 12:44:44 +0000

In Ruby, there is a method called Regexp.escape that escapes any String to be used inside a Regular Expression. This is useful when you want to get the user input and use it inside a RegExp, without breaking it.

In JavaScript, there is no such method, but I found this nice little snippet to create one:

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RegExp.escape = function(s) {
return s.replace(/[-/\\^$*+?.()|[\]{}]/g, '\\$&')
};

Now using:

1	new RegExp( RegExp.escape("jQuery-[1.8]") , "gi" )

Will result /jQuery\-\[1\.8\]/gi

This snippet is very useful and you can probably port it to any other language.

Evernote Dropbox

André Gil — Fri, 31 Aug 2012 14:01:22 +0000

I’ve started using the nice Screen Capture Chrome extension to grab some screenshots for my Evernote web design inspiration collection. The problem is that this extension can’t send the screenshots directly to Evernote, so I needed to do it manually all the time.

After some research, I’ve come up with a better solution to the problem. I’ve developed a small AppleScript to check a folder for new files and e-mail those files to Evernote:

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on adding folder items to this_folder after receiving these_items

repeat with anItem from 1 to number of items in these_items

-- Read file info
set this_item to item anItem of these_items
set the item_info to info for this_item
set the file_name to name of item_info
set the file_extension to name extension of item_info
set the item_path to this_item as text

-- Remove extension from name
if file_extension is not "" then
set _length to (count of file_name) - (count of file_extension) - 1
set the file_name to text 1 thru _length of file_name
end if

-- Start new e-mail
tell application "Mail"

-- Set file name + #tag as subject
set theMessage to make new outgoing message with properties {visible:true, subject:file_name & " #tag #other_tag", content:""}

tell theMessage

-- Add evernote email as recipient
make new to recipient at end of to recipients with properties {name:"Evernote", address:"YOUR_EVERNOTE_EMAIL@m.evernote.com"}

-- Attach file
tell content
make new attachment with properties {file name:item_path} at after last paragraph
end tell

-- Uncomment next line to send the e-mail automatically
-- send

end tell
end tell
end repeat

end adding folder items to

How to use it:

Get your Evernote e-mail address at: https://www.evernote.com/Settings.action
Open the tool “AppleScript Editor”
Copy and paste the script there
Change YOUR_EVERNOTE_EMAIL to your e-mail address
Change #tag #other_tag to any existing tag, if you want, or remove it
Save it as “Mail to Evernote” at “/Library/Scripts/Folder Action Scripts/”
Create a folder anywhere you want. Call it “Evernote Dropbox” or something you like.
Right click this folder, select Services/Folder Actions Setup…
Select the “Mail to Evernote” script
Toggle “Enable Folder Actions”
Uncomment the send command to send the e-mail automatically, if you want

Now save some screenshot at this folder and wait for the new Mail message to be created…

Meetings

André Gil — Fri, 09 Mar 2012 12:42:41 +0000

This morning I found a link that made me remember about this great Coding Horror article about how to have more productive meetings.

Meeting Ticker is basically a “clock”, but instead of time, it show how much money you are spending on your meetings. Money is always a good way to change our behaviour… ;]

Mail Pilot: E-mail, reimagined.

André Gil — Wed, 29 Feb 2012 01:22:21 +0000

We all feel that there is something wrong with “e-mail”, as we know it today. Most people nowadays have more than one e-mail account, our use has been growing exponentially and it’s getting harder and harder to cope with so much information and problems to solve.

So here comes Mail Pilot! A product developed by 2 guys who believe they can reinvent the way we deal with e-mail today. Their Kickstarter project raised $54,205 and they are already working hard on the Beta release.

I’m really looking forward to trying it!

OS X Lion 10.7.3 External Monitor Problem

André Gil — Fri, 24 Feb 2012 12:58:18 +0000

This morning I finally decided to install the latest Mac OS X 10.7.3 update. Everything went better than expected! The only exception was when I connected my external display. The image kept flashing and I couldn’t see anything. After some testing, I think I’ve found the solution:

Open System Preferences.
Click on Displays.
Show display in menu bar.
Click on the menu bar icon.
Check if the selected screen resolution for the external display is appearing twice on the list.
If it’s there twice, select the other one. If it’s not, I’m really sorry!
You can remove the icon from the menu bar now if you want.

Clear for iPhone

André Gil — Wed, 15 Feb 2012 17:20:05 +0000

Clear was finally release today for the iPhone and all I have to say is: Beautiful! I don’t know if I’m gonna use it, but it’s now part of my best designed apps list.