How can I read Chrome Cache files

Question

A forum I frequent was down today  and upon restoration  I discovered that the last two days of forum posting had been rolled back completely    Needless to say  I d like to get back what data I can from the forum loss  and I am hoping I have at least some of it stored in the cache files that Chrome created   I face two problems -- the cache files have no filetype  and I m unsure how to read them in an intelligent manner  trying to open them in Chrome itself seems to  redownload  them in a  gz format   and there are a ton of cache files    Any suggestions on how to read and sort these files   A simple string search should fit my needs

User · Answer

The Google Chrome cache directory  HOME  cache google-chrome Default Cache on Linux contains one file per cache entry named  lt 16 char hex gt  0 in  quot simple entry format quot    20 Byte SimpleFileHeader key  i e  the URI  payload  the raw file content i e  the PDF in our case  SimpleFileEOF record HTTP headers SHA256 of the key  optional  SimpleFileEOF record  If you know the URI of the file you re looking for it should be easy to find  If not  a substring like the domain name  should help narrow it down  Search for URI in your cache like this  fgrep -Rl   lt URI gt    HOME  cache google-chrome Default Cache  Note  If you re not using the default Chrome profile  replace Default with the profile name  e g  Profile 1

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EDIT  The below answer no longer works see here    Google Chrome cache file format description   Cache files list  see URLs  copy and paste to your browser address bar      chrome   cache  chrome   view-http-cache    Cache folder in Linux      cache google-chrome Default Cache  Let s determine in file GZIP encoding     head f84358af102b1064 0   hexdump -C   grep --before-context 100 --after-context 5  1f 8b 08    Extract Chrome cache file by one line on PHP  without header  CRC32 and ISIZE block      php -r  echo gzinflate substr strchr file get contents  f84358af102b1064 0       x1f x8b x08     10  -8

User · Answer

It was removed on purpose and it won t be coming back   Both chrome   cache and chrome   view-http-cache have been removed starting chrome 66   They work in version 65   Workaround  You can check the chrome   chrome-urls  for complete list of internal Chrome URLs   The only workaround that comes into my mind is to use menu more tools developer tools and having a Network tab selected   The reason why it was removed is this bug    https   chromium googlesource com chromium src git   6ebc11f6f6d112e4cca5251d4c0203e18cd79adc https   bugs chromium org p chromium issues detail id 811956   The discussion    https   groups google com a chromium org forum   msg net-dev YNct7Nk6bd8 ODeGPq6KAAAJ

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I ve made short stupid script which extracts JPG and PNG files      usr bin php  lt  php   dir   home user  cache chromium Default Cache     Chrome or chromium cache folder     ppl   home user Desktop temporary       Place for extracted files     list scandir  dir    foreach   list as  filename       if  is file  dir  filename                  cont file get contents  dir  filename           if   strstr  cont  JFIF                          echo   filename    JPEG  n                 start  strpos  cont  JFIF  0 -6                end strpos  cont  HTTP 1 1 200 OK  0                cont substr  cont  start  end-6                wholename  ppl  filename   jpg               file put contents  wholename  cont               echo  Saving     wholename    n                                 elseif   strstr  cont   211PNG                          echo   filename    PNG  n                 start  strpos  cont  PNG  0 -1                end strpos  cont  HTTP 1 1 200 OK  0                cont substr  cont  start  end-1                wholename  ppl  filename   png               file put contents  wholename  cont               echo  Saving     wholename    n                                 else                       echo   filename    UNKNOWN  n                         gt

User · Answer

EDIT  The below answer no longer works see here    In Chrome or Opera  open a new tab and navigate to chrome   view-http-cache   Click on whichever file you want to view  You should then see a page with a bunch of text and numbers  Copy all the text on that page  Paste it in the text box below   Press  Go   The cached data will appear in the Results section below

User · Answer

Note  The below answer is out of date since the Chrome disk cache format has changed   Joachim Metz provides some documentation of the Chrome cache file format with references to further information  For my use case  I only needed a list of cached URLs and their respective timestamps  I wrote a Python script to get these by parsing the data   files under C  Users me AppData Local Google Chrome User Data Default Cache   import datetime with open  data 1    rb   as datafile      data   datafile read    for ptr in range len data        fourBytes   data ptr   ptr   4      if fourBytes    b http              Found the string  http   Hopefully this is a Cache Entry         endUrl   data index b  x00   ptr          urlBytes   data ptr   endUrl          try              url   urlBytes decode  utf-8           except              continue            Extract the corresponding timestamp         try              timeBytes   data ptr - 72   ptr - 64              timeInt   int from bytes timeBytes  byteorder  little               secondsSince1601   timeInt   1000000             jan1601   datetime datetime 1601  1  1  0  0  0              timeStamp   jan1601   datetime timedelta seconds secondsSince1601          except              continue          print         format str timeStamp   19   url

User · Answer

Note  The flag show-saved-copy has been removed and the below answer will not work  You can read cached files using Chrome alone  Chrome has a feature called Show Saved Copy Button   Show Saved Copy Button Mac  Windows  Linux  Chrome OS  Android When a page fails to load  if a stale copy of the page exists in the browser cache  a button will be presented to allow the user to load that stale copy  The primary enabling choice puts the button in the most salient position on the error page  the secondary enabling choice puts it secondary to the reload button   show-saved-copy  First disconnect from the Internet to make sure that browser doesn t overwrite cache entry  Then navigate to chrome   flags  show-saved-copy and set flag value to Enable  Primary  After you restart browser Show Saved Copy Button will be enabled  Now insert cached file URI into browser s address bar and hit enter  Chrome will display There is no Internet connection page alongside with Show saved copy button   After you hit the button browser will display cached file

User · Answer

EDIT  The below answer no longer works see here    If the file you try to recover has Content-Encoding  gzip in the header section  and you are using linux  or as in my case  you have Cygwin installed  you can do the following    visit chrome   view-http-cache  and click the page you want to recover copy the last  fourth  section of the page verbatim to a text file  say  a txt  xxd -r a txt  gzip -d    Note that other answers suggest passing -p option to xxd - I had troubles with that presumably because the fourth section of the cache is not in the  postscript plain hexdump style  but in a  default style     It also does not seem necessary to replace double spaces with a single space  as chrome xxd py is doing  in case it is necessary you can use sed  s      g  for that

User · Answer

EDIT  The below answer no longer works see here    Chrome stores the cache as a hex dump  OSX comes with xxd installed  which is a command line tool for converting hex dumps  I managed to recover a jpg from my Chrome s HTTP cache on OSX using these steps    Goto  chrome   cache Find the file you want to recover and click on it s link  Copy the 4th section to your clipboard  This is the content of the file   Follow the steps on this gist to pipe your clipboard into the python script which in turn pipes to xxd to rebuild the file from the hex dump  https   gist github com andychase 6513075   Your final command should look like   pbpaste   python chrome xxd py   xxd -r - image jpg  If you re unsure what section of Chrome s cache output is the content hex dump take a look at this page for a good guide   http   www sparxeng com blog wp-content uploads 2013 03 chrome cache html report png  Image source  http   www sparxeng com blog software recovering-images-from-google-chrome-browser-cache  More info on XXD  http   linuxcommand org man pages xxd1 html  Thanks to Mathias Bynens above for sending me in the right direction

User · Answer

Try Chrome Cache View from NirSoft  free

User · Answer

I had some luck with this open-source Python project  seemingly inactive  https   github com JRBANCEL Chromagnon  I ran   python2 Chromagnon chromagnonCache py path to Chrome Cache -o browsable cache    And I got a locally-browsable extract of all my open tabs cache

User · Answer

The JPEXS Free Flash Decompiler has Java code to do this at in the source tree for both Chrome and Firefox  no support for Firefox s more recent cache2 though

[google-chrome] How can I read Chrome Cache files?

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