我尝试在使用此代码向API发送请求之前压缩图像：
require 'sinatra'
require 'unirest'
require 'mini_magick'
require 'json'
require 'open-uri'
get '/' do
File.read('public/views/index.erb')
end
post '/' do
Unirest.timeout(5)
image = MiniMagick::Image.open(params['user_image'][:tempfile])
image.resize "600x400"
response = Unirest.post 'https://search.craftar.net/v1/search',
parameters: {
token: "703eb042371c49f0",
image: image
}
body = response.body
url = body['results'][0]['item']['url']
redirect url
end
当它运行以获得结果时，我收到以下错误：
ArgumentError at /
wrong number of arguments (1 for 0)
/usr/local/Cellar/ruby/2.2.3/lib/ruby/2.2.0/tempfile.rb in open
def open
/usr/local/Cellar/ruby/2.2.3/lib/ruby/2.2.0/open-uri.rb in open
name.open(*rest, &block)
/usr/local/lib/ruby/gems/2.2.0/gems/mini_magick-4.3.6/lib/mini_magick/image.rb in open
Kernel.open(path_or_url, "rb") do |file|
server.rb in block in <main>
image = MiniMagick::Image.open(params['user_image'][:tempfile])
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call
proc { |a,p| unbound_method.bind(a).call }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in compile!
proc { |a,p| unbound_method.bind(a).call }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in []
route_eval { block[*args] }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block (3 levels) in route!
route_eval { block[*args] }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in route_eval
throw :halt, yield
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block (2 levels) in route!
route_eval { block[*args] }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in process_route
block ? block[self, values] : yield(self, values)
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in catch
catch(:pass) do
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in process_route
catch(:pass) do
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in route!
returned_pass_block = process_route(pattern, keys, conditions) do |*args|
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in each
routes.each do |pattern, keys, conditions, block|
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in route!
routes.each do |pattern, keys, conditions, block|
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in dispatch!
route!
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in invoke
res = catch(:halt) { yield }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in catch
res = catch(:halt) { yield }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in invoke
res = catch(:halt) { yield }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in dispatch!
invoke do
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in call!
invoke { dispatch! }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in invoke
res = catch(:halt) { yield }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in catch
res = catch(:halt) { yield }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in invoke
res = catch(:halt) { yield }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call!
invoke { dispatch! }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call
dup.call!(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-protection-1.5.3/lib/rack/protection/xss_header.rb in call
status, headers, body = @app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-protection-1.5.3/lib/rack/protection/path_traversal.rb in call
app.call env
/usr/local/lib/ruby/gems/2.2.0/gems/rack-protection-1.5.3/lib/rack/protection/json_csrf.rb in call
status, headers, body = app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-protection-1.5.3/lib/rack/protection/base.rb in call
result or app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-protection-1.5.3/lib/rack/protection/base.rb in call
result or app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-protection-1.5.3/lib/rack/protection/frame_options.rb in call
status, headers, body = @app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/logger.rb in call
@app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/commonlogger.rb in call
status, header, body = @app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call
call_without_check(env)
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call
env['sinatra.commonlogger'] ? @app.call(env) : super
/usr/local/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/head.rb in call
status, headers, body = @app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/methodoverride.rb in call
@app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/show_exceptions.rb in call
@app.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call
result, callback = app.call(env), env['async.callback']
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call
@stack.call(env)
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in block in call
synchronize { prototype.call(env) }
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in synchronize
yield
/usr/local/lib/ruby/gems/2.2.0/gems/sinatra-1.4.6/lib/sinatra/base.rb in call
synchronize { prototype.call(env) }
/usr/local/lib/ruby/gems/2.2.0/gems/rack-1.6.4/lib/rack/handler/webrick.rb in service
status, headers, body = @app.call(env)
/usr/local/Cellar/ruby/2.2.3/lib/ruby/2.2.0/webrick/httpserver.rb in service
si.service(req, res)
/usr/local/Cellar/ruby/2.2.3/lib/ruby/2.2.0/webrick/httpserver.rb in run
server.service(req, res)
/usr/local/Cellar/ruby/2.2.3/lib/ruby/2.2.0/webrick/server.rb in block in start_thread
block ? block.call(sock) : run(sock)
如果这不起作用，我如何提取临时存储的用户上传的图像，并将其压缩到API所需的特定要求。
非常感谢任何帮助！
答案 0 :(得分：0)
image.rb中的代码在tempfile上调用Kernel.open。这从open-uri.rb调用open，如果对象响应，则调用open。临时文件响应open，但不接受来自image.rb的'rb'param open-uri委托。
我认为最简单的解决方案是将临时文件包装到普通文件中并从那里开始：
image = MiniMagick::Image.open(File.new(params[:user_image][:tempfile]))
代码仍然失败，但我认为MiniMagick中的错误（unrecognized option -to-ary'）是无关的。