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Diffstat (limited to 'sx-request.el')
| -rw-r--r-- | sx-request.el | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/sx-request.el b/sx-request.el new file mode 100644 index 0000000..a62ee0e --- /dev/null +++ b/sx-request.el @@ -0,0 +1,194 @@ +;;; sx-request.el --- requests for stack-mode + +;; Copyright (C) 2014 Sean Allred + +;; Author: Sean Allred <sallred@calamity.tcs.com> +;; Keywords: + +;; This program is free software; you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. + +;; This program is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with this program. If not, see <http://www.gnu.org/licenses/>. + +;;; Commentary: + +;; + +;;; Code: +(require 'json) +(require 'url) +(require 'sx) + +(defcustom sx-request-silent-p + t + "When `t', requests default to being silent.") + +(defcustom sx-request-cache-p + t + "Cache requests made to the StackExchange API.") + +(defcustom sx-request-unzip-program + "gunzip" + "program used to unzip the response") + +(defvar sx-request-remaining-api-requests + nil + "The number of API requests remaining according to the most +recent call. Set by `sx-request-make'.") + +(defcustom sx-request-remaining-api-requests-message-threshold + 50 + "After `sx-request-remaining-api-requests' drops below this +number, `sx-request-make' will begin printing out the +number of requests left every time it finishes a call.") + +(defcustom sx-request-default-keyword-arguments-alist + '(("filters/create") + ("sites") + ("questions" (site . emacs)) + (t nil)) + "Keywords to use as the default for a given method. + +The first element of each list is the method call the keywords +apply to. The remaining cons cells (and they must be conses) are +the values for each keyword. + +For each list, if no keywords are provided, the method's +arguments are forced to the default as determined by the API. + +For each cons cell, if the cdr is `nil', then the keyword will be +forced to the default as determined by the API. + +See `sx-request-get-default-keyword-arguments' and +`sx-request-build-keyword-arguments'. +") + +(defconst sx-request-api-version + "2.2" + "The current version of the API.") + +(defconst sx-request-api-root + (format "http://api.stackexchange.com/%s/" sx-request-api-version) + "The base URL to make requests from.") + +(defconst sx-request-api-key + "0TE6s1tveCpP9K5r5JNDNQ((" + "When passed, this key provides a higher request quota.") + +(defun sx-request-make + (method &optional keyword-arguments filter silent) + "Make a request to the StackExchange API using METHOD and +optional KEYWORD-ARGUMENTS. If no KEYWORD-ARGUMENTS are given, +`sx-default-keyword-arguments-alist' is used. Return the +entire response as a complex alist." + (let ((url-automatic-caching sx-request-cache-p) + (url-inhibit-uncompression t) + (silent (or silent sx-request-silent-p)) + (call + (sx-request--build + method + (append `((filter . ,(cond (filter filter) + ((boundp 'stack-filter) stack-filter))) + (key . ,sx-request-api-key)) + (if keyword-arguments keyword-arguments + (sx-request--get-default-keyword-arguments method)))))) + ;; TODO: url-retrieve-synchronously can return nil if the call is + ;; unsuccessful should handle this case + (unless silent (sx-message "Request: %S" call)) + (let ((response-buffer (cond + ((= emacs-minor-version 4) + (url-retrieve-synchronously call silent)) + (t (url-retrieve-synchronously call))))) + (if (not response-buffer) + (error "Something went wrong in `url-retrieve-synchronously'") + (with-current-buffer response-buffer + (let* ((data (progn + (goto-char (point-min)) + (if (not (search-forward "\n\n" nil t)) + (error "Response headers missing") + (delete-region (point-min) (point)) + (buffer-string)))) + (response (ignore-errors + (json-read-from-string data)))) + ;; if response isn't nil, the response was in plain text + (unless response + ;; try to decompress the response + (setq response + (with-demoted-errors "JSON Error: %s" + (shell-command-on-region + (point-min) (point-max) + sx-request-unzip-program + nil t) + (json-read-from-string + (buffer-substring + (point-min) (point-max))))) + ;; If it still fails, error out + (unless response + (sx-message "Unable to parse response") + (sx-message "Printing response as message") + (message "%S" response) + (error "Response could not be read by json-read-string"))) + ;; At this point, either response is a valid data structure + ;; or we have already thrown an error + (when (assoc 'error_id response) + (error "Request failed: (%s) [%i %s] %s" + method + (cdr (assoc 'error_id response)) + (cdr (assoc 'error_name response)) + (cdr (assoc 'error_message response)))) + (when (< (setq sx-request-remaining-api-requests + (cdr (assoc 'quota_remaining response))) + sx-request-remaining-api-requests-message-threshold) + (sx-message "%d API requests remaining" + sx-request-remaining-api-requests)) + (cdr (assoc 'items response)))))))) + +(defun sx-request--build (method keyword-arguments &optional kv-value-sep) + "Build the request string that will be used to process REQUEST +with the given KEYWORD-ARGUMENTS." + (let ((base (concat sx-request-api-root method)) + (args (sx-request--build-keyword-arguments + keyword-arguments kv-value-sep))) + (if (string-equal "" args) + base + (concat base "?" args)))) + +(defun sx-request--build-keyword-arguments (alist &optional kv-value-sep) + "Build a \"key=value&key=value&...\"-style string with the elements +of ALIST. If any value in the alist is `nil', that pair will not +be included in the return. If you wish to pass a notion of +false, use the symbol `false'. Each element is processed with +`sx--thing-as-string'." + (mapconcat + (lambda (pair) + (concat + (sx--thing-as-string (car pair)) + "=" + (sx--thing-as-string (cdr pair) kv-value-sep))) + (delq nil (mapcar + (lambda (pair) + (when (cdr pair) pair)) + alist)) + "&")) + +(defun sx-request--get-default-keyword-arguments (method) + "Gets the correct keyword arguments for METHOD." + (let ((entry (assoc method sx-request-default-keyword-arguments-alist))) + (cdr (or entry (assoc t sx-request-default-keyword-arguments-alist))))) + +;;; @todo sx-request-change-default-keyword-arguments +;;; (method new-keyword-arguments) +;;; @todo sx-request-change-default-keyword-arguments-for-key +;;; (method key new-value) + + +(provide 'sx-request) +;;; sx-request.el ends here |