{"id":956,"date":"2013-08-14T17:51:25","date_gmt":"2013-08-14T22:51:25","guid":{"rendered":"http:\/\/osric.com\/chris\/accidental-developer\/?p=956"},"modified":"2013-08-14T17:51:25","modified_gmt":"2013-08-14T22:51:25","slug":"using-a-lightweight-web-server-to-debug-requests","status":"publish","type":"post","link":"https:\/\/osric.com\/chris\/accidental-developer\/2013\/08\/using-a-lightweight-web-server-to-debug-requests\/","title":{"rendered":"Using a lightweight web server to debug requests"},"content":{"rendered":"

I’ve been working a lot with the Canvas API<\/a> lately. One task was to add communication channels<\/a> (e-mail addresses) to user accounts. I was able to add them successfully following the documentation’s cURL example using the skip_confirmation flag:<\/p>\n

curl 'https:\/\/mycanvas.instructure.com\/api\/v1\/users\/[user id]\/communication_channels'
\n -H \"Authorization: Bearer [...]\"
\n -d 'communication_channel[address]=chris@osric.com'
\n -d 'communication_channel[type]=email'
\n -d 'skip_confirmation=1'<\/code><\/p>\n

However, when I ran the ColdFusion script I wrote, the user received notification of the addition even though the skip_confirmation flag was set:<\/p>\n

<cfhttp url=\"https:\/\/mycanvas.instructure.com\/api\/v1\/users\/[user id]\/communication_channels\" method=\"post\">
\n <cfhttpparam type=\"header\" name=\"Authorization\" value=\"Bearer [...]\" \/>
\n <cfhttpparam type=\"formfield\" name=\"communication_channel[address]\" value=\"chris@osric.com\" \/>
\n <cfhttpparam type=\"formfield\" name=\"communication_channel[type]\" value=\"email\" \/>
\n <cfhttpparam type=\"formfield\" name=\"skip_confirmation\" value=\"1\" \/>
\n<\/cfhttp><\/code><\/p>\n

Why didn’t the latter work as expected?<\/p>\n

I needed to be able to tell what was different about the 2 requests, but it would be difficult to capture that outbound requests. Tools like Fiddler<\/a> and WireShark<\/a> could help, but I was sending one request from my local machine and another from a remote web server.<\/p>\n

My idea for capturing the request data was to send the request to a server under my control. I grabbed a Python echo server<\/a> and modified it slightly to print the data received. Then, instead of sending the requests to the Canvas API I sent them to the echo server. Here are the results of the 2 requests:<\/p>\n

cURL<\/strong>
\nPOST \/ HTTP\/1.1
\nUser-Agent: curl\/7.24.0 (i686-pc-cygwin) libcurl\/7.24.0 OpenSSL\/0.9.8t zlib\/1.2.5 libidn\/1.22 libssh2\/1.3.0
\nHost: osric.com:50000
\nAccept: *\/*
\nAuthorization: Bearer [...]
\nContent-Length: 100
\nContent-Type: application\/x-www-form-urlencoded<\/p>\n

communication_channel[address]=chris@osric.com&communications_channel[type]=email&skip_confirmation=1<\/code><\/p>\n

ColdFusion<\/strong>
\nPOST \/ HTTP\/1.1
\nUser-Agent: ColdFusion
\nContent-Type: application\/x-www-form-urlencoded
\nConnection: close
\nAuthorization: Bearer [...]
\nContent-Length: 118
\nHost: osric.com:50000<\/p>\n

communication%5Fchannel%5Baddress%5D=chris%40osric%2Ecom&communications%5Fchannel%5Btype%5D=email&skip%5Fconfirmation=1<\/code><\/p>\n

I noted the different content lengths for the same data, and upon closer inspection, ColdFusion was URL-encoding characters. I added the encoded<\/em> attribute to the cfhttpparam tags with a value of “no”, and then the request bodies were identical:<\/p>\n

<cfhttp url=\"https:\/\/mycanvas.instructure.com\/api\/v1\/users\/[user id]\/communication_channels\" method=\"post\">
\n <cfhttpparam type=\"header\" name=\"Authorization\" value=\"Bearer [...]\" \/>
\n <cfhttpparam type=\"formfield\" encoded=\"no\" name=\"communication_channel[address]\" value=\"chris@osric.com\" \/>
\n <cfhttpparam type=\"formfield\" encoded=\"no\" name=\"communication_channel[type]\" value=\"email\" \/>
\n <cfhttpparam type=\"formfield\" encoded=\"no\" name=\"skip_confirmation\" value=\"1\" \/>
\n<\/cfhttp><\/code><\/p>\n

Not surprisingly that solved the problem.<\/p>\n","protected":false},"excerpt":{"rendered":"

I’ve been working a lot with the Canvas API lately. One task was to add communication channels (e-mail addresses) to user accounts. I was able to add them successfully following the documentation’s cURL example using the skip_confirmation flag: curl ‘https:\/\/mycanvas.instructure.com\/api\/v1\/users\/[user id]\/communication_channels’ -H “Authorization: Bearer […]” -d ‘communication_channel[address]=chris@osric.com’ -d ‘communication_channel[type]=email’ -d ‘skip_confirmation=1’ However, when I ran … Continue reading Using a lightweight web server to debug requests<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,18],"tags":[308,309,299,300,349,215,310,358,311,307],"class_list":["post-956","post","type-post","status-publish","format-standard","hentry","category-coldfusion","category-debugging","tag-canvas","tag-canvas-api","tag-cfhttp","tag-cfhttpparam","tag-coldfusion","tag-curl","tag-echo-server","tag-python","tag-request-debugging","tag-url-encoding"],"_links":{"self":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts\/956","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/comments?post=956"}],"version-history":[{"count":4,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts\/956\/revisions"}],"predecessor-version":[{"id":961,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts\/956\/revisions\/961"}],"wp:attachment":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/media?parent=956"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/categories?post=956"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/tags?post=956"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}