前言
想要做全文搜索引擎，則需要將word/pdf等文檔內容提取出來。對于pdf有xpdf等一些開源方案。
但Word文檔的情況則會復雜一些。
提取PDF文本內容
XPDF是一個免費開源的軟件，用于顯示PDF文件，并可將pdf轉換成文字圖片等，同樣支持Windows版。在Debian Linux上安裝非常簡單:
apt-get install xpdf
我們這里只使用pdftotext這個功能，直接輸入可查看幫助：
root@raspberrypi:/var/www# pdftotextpdftotext version 0.26.5Copyright 2005-2014 The Poppler Developers - http://poppler.freedesktop.orgCopyright 1996-2011 Glyph & Cog, LLCUsage: pdftotext [options] <PDF-file> [<text-file>] -f <int> : first page to convert -l <int> : last page to convert -r <fp> : resolution, in DPI (default is 72) -x <int> : x-coordinate of the crop area top left corner -y <int> : y-coordinate of the crop area top left corner -W <int> : width of crop area in pixels (default is 0) -H <int> : height of crop area in pixels (default is 0) -layout : maintain original physical layout -fixed <fp> : assume fixed-pitch (or tabular) text -raw : keep strings in content stream order -htmlmeta : generate a simple HTML file, including the meta information -enc <string> : output text encoding name -listenc : list available encodings -eol <string> : output end-of-line convention (unix, dos, or mac) -nopgbrk : don't insert page breaks between pages -bbox : output bounding box for each word and page size to html. Sets -htmlmeta -opw <string> : owner password (for encrypted files) -upw <string> : user password (for encrypted files) -q : don't print any messages or errors -v : print copyright and version info -h : print usage information -help : print usage information --help : print usage information -? : print usage information
測試一下：
root@raspberrypi:/var/www# pdftotext onceai.pdf onceai.txtroot@raspberrypi:/var/www# cat onceai.txt 產品介紹 頑石智能科技（上海）有限公司....
然后在node.js中使用 child_process直接調用此命令即可，pdftotext會將內容輸出以文本文件中，可能需要多一些操作。具體代碼略。
用antiword提取 .doc 的內容
我們這里使用了 antiword 開源軟件，來提取word2003以前版本的內容，安裝同樣非常簡單：
apt-get install antiword
查看幫助：
root@raspberrypi:/var/www# antiword Name: antiword Purpose: Display MS-Word files Author: (C) 1998-2005 Adri van Os Version: 0.37 (21 Oct 2005) Status: GNU General Public License Usage: antiword [switches] wordfile1 [wordfile2 ...] Switches: [-f|-t|-a papersize|-p papersize|-x dtd][-m mapping][-w #][-i #][-Ls] -f formatted text output -t text output (default) -a <paper size name> Adobe PDF output -p <paper size name> PostScript output paper size like: a4, letter or legal -x <dtd> XML output like: db (DocBook) -m <mapping> character mapping file -w <width> in characters of text output -i <level> image level (PostScript only) -L use landscape mode (PostScript only) -r Show removed text -s Show hidden (by Word) text
antiword直接將word內容輸出到了console中：