Rails 3.2，处理损坏的请求体（MultiJson :: DecodeError）
我正在研究Rails 3.2.11应用程序（MRI 1.9.3）。
它的PArt是一个Web服务，它接收带有JSON序列化主体的POST请求。
一切正常，但我希望它能够抵御错误的格式化请求，例如无效的JSON。
现在，如果它收到一个JSON – 比方说 – 缺少一个逗号，它将返回一个500错误，其中包含默认rails错误视图的HTML响应（加上dev中的回溯）。
我想自定义它以返回带有错误信息的JSON或XML响应。
错误是MultiJson::DecodeError ，我知道我可以在ApplicationController中使用rescue_from捕获exception……但它似乎不起作用。
这就像错误发生在正常请求流之外。
这是我的代码（一旦我开始工作，我将使用更多数据扩展错误消息）：
class ApplicationController "the request body was not acceptable" } respond_to do |format| format.html { redirect_to :root, notice: "invalid params" } format.xml { render :xml => @response, status: 400 } format.json { render :json => @response, status: 400 } end end end
这是回溯：
MultiJson::DecodeError (795: unexpected token at '{ "json_with_missing_comma" : { "foo" : "qqqqqqqqqqqqqqq" "bar" : "aaaaaaaaaaaaaa" }}'): json (1.7.6) lib/json/common.rb:155:in `parse' json (1.7.6) lib/json/common.rb:155:in `parse' multi_json (1.5.0) lib/multi_json/adapters/json_common.rb:7:in `load' multi_json (1.5.0) lib/multi_json.rb:96:in `load' activesupport (3.2.11) lib/active_support/json/decoding.rb:15:in `decode' actionpack (3.2.11) lib/action_dispatch/middleware/params_parser.rb:47:in `parse_formatted_parameters' actionpack (3.2.11) lib/action_dispatch/middleware/params_parser.rb:17:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/flash.rb:242:in `call' rack (1.4.4) lib/rack/session/abstract/id.rb:210:in `context' rack (1.4.4) lib/rack/session/abstract/id.rb:205:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/cookies.rb:341:in `call' activerecord (3.2.11) lib/active_record/query_cache.rb:64:in `call' activerecord (3.2.11) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call' activesupport (3.2.11) lib/active_support/callbacks.rb:405:in `_run__1562301902235545482__call__1964551201027599208__callbacks' activesupport (3.2.11) lib/active_support/callbacks.rb:405:in `__run_callback' activesupport (3.2.11) lib/active_support/callbacks.rb:385:in `_run_call_callbacks' activesupport (3.2.11) lib/active_support/callbacks.rb:81:in `run_callbacks' actionpack (3.2.11) lib/action_dispatch/middleware/callbacks.rb:27:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/reloader.rb:65:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/remote_ip.rb:31:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call' railties (3.2.11) lib/rails/rack/logger.rb:32:in `call_app' railties (3.2.11) lib/rails/rack/logger.rb:16:in `block in call' activesupport (3.2.11) lib/active_support/tagged_logging.rb:22:in `tagged' railties (3.2.11) lib/rails/rack/logger.rb:16:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/request_id.rb:22:in `call' rack (1.4.4) lib/rack/methodoverride.rb:21:in `call' rack (1.4.4) lib/rack/runtime.rb:17:in `call' activesupport (3.2.11) lib/active_support/cache/strategy/local_cache.rb:72:in `call' rack (1.4.4) lib/rack/lock.rb:15:in `call' actionpack (3.2.11) lib/action_dispatch/middleware/static.rb:62:in `call' railties (3.2.11) lib/rails/engine.rb:479:in `call' railties (3.2.11) lib/rails/application.rb:223:in `call' rack (1.4.4) lib/rack/content_length.rb:14:in `call' railties (3.2.11) lib/rails/rack/log_tailer.rb:17:in `call' thin (1.5.0) lib/thin/connection.rb:81:in `block in pre_process' thin (1.5.0) lib/thin/connection.rb:79:in `catch' thin (1.5.0) lib/thin/connection.rb:79:in `pre_process' thin (1.5.0) lib/thin/connection.rb:54:in `process' thin (1.5.0) lib/thin/connection.rb:39:in `receive_data' eventmachine (1.0.0) lib/eventmachine.rb:187:in `run_machine' eventmachine (1.0.0) lib/eventmachine.rb:187:in `run' thin (1.5.0) lib/thin/backends/base.rb:63:in `start' thin (1.5.0) lib/thin/server.rb:159:in `start' rack (1.4.4) lib/rack/handler/thin.rb:13:in `run' rack (1.4.4) lib/rack/server.rb:268:in `start' railties (3.2.11) lib/rails/commands/server.rb:70:in `start' railties (3.2.11) lib/rails/commands.rb:55:in `block in ' railties (3.2.11) lib/rails/commands.rb:50:in `tap' railties (3.2.11) lib/rails/commands.rb:50:in `' script/rails:6:in `require' script/rails:6:in `'
gem： https ： //github.com/kares/request_exception_handler以及以下行为我工作。
在Application controller中：“rescue_from’REXML :: ParseException’do | exception | render：text =>”Bad Request：XML parse exception“，：status => 422 end
rescue_from’MultiJson :: DecodeError’do | exception | render：text =>“错误请求：JSON解析exception”，：status => 422 end“