在 Emacs 中集成 Recoll 全文搜索

Posted 2021-03-25 bu-wu-zheng-ye

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1 需求

时间一长，平常收集的资料就多了，于是使用了 recoll 全文搜索，但是在Emacs 中工作时间多，搜索要在 Emacs 和 Recoll 图形界面中来回切换，很不方便。而且，如果本地文件中找不到，要用搜索引擎到网上搜索的话就更麻烦了，于是想能不能把这需要整合一下，平时找东西直接开 Recoll 搜索，如果没有的话可以一键切到 Google 搜索结果。

2 解决办法

原来的办法

这是在网上搜索到的办法，最大的问题就是你看不到摘要，只有在 minibuffer 中看文件名猜其中有啥，如果不是你想要的东西，还得再输入搜索字符串，重来一回，比在 recoll 图形界面中还要麻烦。

(defun counsel-recoll-function (string &rest _unused)
  "Issue recallq for STRING."
  (if (< (length string) 3)
      (counsel-more-chars 3)
    (counsel--async-command
     (format "recollq -b ‘%s‘" string))
    nil))


(defun counsel-recoll (&optional initial-input)
  "Search for a string in the recoll database.
You‘ll be given a list of files that match.
Selecting a file will launch `swiper‘ for that file.
INITIAL-INPUT can be given as the initial minibuffer input."
  (interactive)
  (ivy-read "recoll: " ‘counsel-recoll-function
            :initial-input initial-input
            :dynamic-collection t
            :history ‘counsel-git-grep-history
            :action (lambda (x)
                      (when (string-match "file://\(.*\)\‘" x)
                        (let ((file-name (match-string 1 x)))
                          (find-file file-name)
                          (unless (string-match "pdf$" x)
                            (swiper ivy-text)))))))

我的解决办法

使用 "recoll -t -A query" 输出查询结果到 Emacs 缓冲中，包含摘要等内容，然后构建成 html 文档，再用 `eww-display-html‘ 来显示缓冲。

(defvar recoll-to-html-temmplate "~/Templates/recoll-to-html-template.html")
(defun recoll-to-html(query)
  "Use recoll search local file as eww, require `org‘,`eww‘,and recoll installed and indexed.
You can press `n‘ to call `eww-next-url‘ google the QUERY."
  (interactive "sSearch Words:")
  (require ‘org)
  (require ‘eww)
  (let ((source nil)
        (google-search-url (format "http://www.google.com/search?q=%s" (url-hexify-string query)))
        (content-tail-marker nil)
        (buffer (get-buffer-create "*recoll*")))
    (with-current-buffer buffer
      (setq inhibit-read-only t )
      (display-buffer buffer)
      (erase-buffer)
      ;; insert template and goto the body insert point
      (insert-file-contents (expand-file-name recoll-to-html-temmplate))
      (if (not  (re-search-forward "<body>
</body>" nil t))
          (message "Invalid html template")
        )
      (goto-char (- (point) 7))
      (setq marker-beg (point))
      ;; insert the search result
      (insert
       (shell-command-to-string
        (format "recoll -t -A ‘%s‘" query)))
      (setq content-tail-marker (point))
      ;; change the keyword display color
      (goto-char (point-min))
      (while (re-search-forward "
ABSTRACT
\(.+\)
/ABSTRACT" nil t)
        (save-restriction
          (narrow-to-region (match-beginning 1) (match-end 1))
          (goto-char (point-min))
          (replace-string query  (concat  "<span style="color:#F00">" query "</span>" ))
          )
        )

      ;; insert paragraph tags
      (narrow-to-region marker-beg (point-max))
      (goto-char (point-min))
      (insert "<h1>")
      (goto-char (point-min))
      (forward-line 2)
      (insert "</h1>" "
<p>Search with Google:  <a href="" google-search-url "">" query "</a></p>" "
<p>")
      (goto-char (point-min))
      (replace-string "
ABSTRACT
" "</p>
<p>")
      (goto-char (point-min))
      (replace-string "
/ABSTRACT
" "</p>
<p>")
      (goto-char (point-min))
      (replace-string "
/ABSTRACT" "</p>
<p>")
      (goto-char (point-max))
      (insert "</p>")
      (goto-char (point-min))
      (while (re-search-forward "bytes
\([
]+\)" nil t)
        (delete-region (match-beginning 1) (match-end 1))
        )
      ;; construct html url href
      (goto-char (point-min))
      (while (re-search-forward "\[\(.*\)\] \[\(.*\)\]" nil t)
        (let ((match-len (length (match-string 0)))
              (esc-str (org-link-escape (match-string 1)))
              (display-str  (match-string 2))
              (marker-max (point))
              )
          (delete-region (- marker-max match-len) marker-max)
          (insert "<a href="" esc-str "">" display-str "</a>")
          )
        )
      (goto-char (point-max))
      (insert "
<p>Search with Google:  <a href="" google-search-url "">" query "</a></p>")
      (widen)
      (setq source (buffer-string))
      ;; display as html by eww
      (goto-char (point-min))
      (eww-display-html ‘utf-8 nil nil (point-min) buffer)
      (linum-mode t)
      (read-only-mode t)
      (eww-mode)
      )
    (with-current-buffer buffer
      (plist-put eww-data :url "Recoll") ;;here any string make `eww-next-url‘ work
      (plist-put eww-data :source source) ;; used for debug
      (plist-put eww-data :next google-search-url) ;; you can press `n‘ google the query
      (plist-put eww-data :title "RECOLL SEARCH RESULTS")
      (eww-update-header-line-format)
      (let ((old-data eww-data))
        (eww-save-history)
        (setq eww-history-position 0)
        (dolist (elem ‘(:source :url :title :next ))
          (plist-put eww-data elem (plist-get old-data elem)))
        (run-hooks ‘eww-after-render-hook)))
    ))

但有个问题就是回退的时候，退不到我们的索引页面，原因是 `eww-follow-link‘ 中检查了访问 url 的构成，只有同一个页面的才会调用 `eww-save-history‘，我不知道作者是怎么考虑的，反正我给加个补丁，不管到什么 url 都调用 `eww-save-history‘ 保存当前页面。

第二是他可能会使用外部浏览器打开页面。其实，Emacs 支持打开的页面已经完全可以满足我的需要了，于是将 `browse-url-browser-function‘ 设置为 `eww-browse-url‘。

(setq browse-url-browser-function ‘eww-browse-url)
(setq shr-external-browser (lambda (url &rest args) (apply ‘browse-url-xdg-open url args)))
(eval-after-load ‘browse-url
  ‘(defun browse-url-default-browser (url &rest args)
     " Use EWW as the default browser for search web package. But
you should set the variable `shr-external-browser‘ to
browse-url-xdg-open to make `eww-browse-with-external-browser‘ to
work as expected."
     (apply ‘eww-browse-url
            url args)))

(defun eww-follow-link-before-advice (&optional external mouse-event)
  (eww-save-history)
  )
(advice-add ‘eww-follow-link :before #‘eww-follow-link-before-advice)