{"id":189,"date":"2011-08-23T10:14:30","date_gmt":"2011-08-23T14:14:30","guid":{"rendered":"http:\/\/digitallibraryworld.com\/?p=189"},"modified":"2014-03-31T18:01:04","modified_gmt":"2014-03-31T22:01:04","slug":"http-or-https-post-in-android-using-httpurlconnection","status":"publish","type":"post","link":"https:\/\/heisbudi.com\/?p=189","title":{"rendered":"HTTP or HTTPS Post in Android using HTTPURLConnection"},"content":{"rendered":"

I’m starting to dive deep into Android world. The first step is usually the hardest. I’m starting to grasp how the Android environment operates. The best way for me to learn is by reading, and actually doing it. So, I started to build a room reservation app using an web service API built by my co-worker. Calling this API requires HTTP POST call from Android. This is where it gets interesting. I tried scouring the web for hours, and all the example I found did not work! I finally looked into android documentation<\/a>, which is really where I should started first. It seems so simple. I could do it in 10 seconds in c#. However during my trial, all the post parameters are not recognized by the API, which is written using PHP. I’ll describe some of the mistake I made.<\/p>\n

\/\/import these on your header<\/p>\n

import java.io.IOException;<\/span><\/div>\n
import java.io.PrintWriter;
\n<\/span><\/div>\n
import java.net.HttpURLConnection;<\/span><\/div>\n
import java.net.MalformedURLException;<\/span><\/div>\n
import java.net.ProtocolException;<\/span><\/div>\n
import java.net.URL;<\/span><\/div>\n
import java.net.URLEncoder;<\/span><\/div>\n
import java.util.Scanner;<\/span><\/div>\n

\/\/do this wherever you are wanting to POST
\n URL url;
\nHttpURLConnection conn;
\n<\/span><\/p>\n

try{<\/span>
\n\/\/if you are using https, make sure to import java.net.HttpsURLConnection
\n url=new URL(“http:\/\/somesite\/somefile.php”);<\/span><\/p>\n

\/\/you need to encode ONLY the values of the parameters
\n String param=”param1=” + URLEncoder.encode(“value1″,”UTF-8”)+
\n“&param2=”+URLEncoder.encode(“value2″,”UTF-8”)+
\n“&param3=”+URLEncoder.encode(“value3″,”UTF-8”);<\/span><\/p>\n

conn=(HttpURLConnection)url.openConnection();<\/span>
\n\/\/set the output to true, indicating you are outputting(uploading) POST data
\n conn.setDoOutput(true);<\/span>
\n\/\/once you set the output to true, you don’t really need to set the request method to post, but I’m doing it anyway
\n conn.setRequestMethod(“POST”);<\/span><\/p>\n

\/\/Android documentation suggested that you set the length of the data you are sending to the server, BUT
\n\/\/ do NOT specify this length in the header by using conn.setRequestProperty(“Content-Length”, length);
\n\/\/use this instead.
\nconn.setFixedLengthStreamingMode(param.getBytes().length);<\/span>
\nconn.setRequestProperty(“Content-Type”, “application\/x-www-form-urlencoded”);<\/span>
\n\/\/send the POST out
\nPrintWriter out = new PrintWriter(conn.getOutputStream());
\nout.print(param);
\nout.close();<\/span><\/p>\n

\/\/build the string to store the response text from the server
\n String response= “”;<\/span><\/p>\n

\/\/start listening to the stream
\nScanner inStream = new Scanner(conn.getInputStream()); <\/span><\/p>\n

\/\/process the stream and store it in StringBuilder
\nwhile(inStream.hasNextLine())
\n<\/span> response+=(inStream.nextLine());<\/span><\/p>\n

}
\n\/\/catch some error<\/span>
\ncatch(MalformedURLException ex){<\/span><\/span>
\n<\/span> Toast.makeText(MyActivity.this, ex.toString(), 1 ).show();<\/span>
\n<\/span>}
\n\/\/ and some more<\/span>
\n<\/span>catch(IOException ex){<\/span><\/span><\/p>\n

Toast.makeText(MyActivity.this, ex.toString(), 1 ).show();
\n<\/span> } <\/span><\/p>\n

That’s it. Whatever output you receive from the URL you are calling would be stored in response<\/span> string.<\/span><\/p>\n

<\/a><\/a><\/a><\/a><\/div>
<\/a><\/a><\/a><\/a><\/div>","protected":false},"excerpt":{"rendered":"

Doing HTTP POST or HTTPS POST in android using HttpUrlConnection<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[20],"tags":[38],"_links":{"self":[{"href":"https:\/\/heisbudi.com\/index.php?rest_route=\/wp\/v2\/posts\/189"}],"collection":[{"href":"https:\/\/heisbudi.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/heisbudi.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/heisbudi.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/heisbudi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=189"}],"version-history":[{"count":8,"href":"https:\/\/heisbudi.com\/index.php?rest_route=\/wp\/v2\/posts\/189\/revisions"}],"predecessor-version":[{"id":477,"href":"https:\/\/heisbudi.com\/index.php?rest_route=\/wp\/v2\/posts\/189\/revisions\/477"}],"wp:attachment":[{"href":"https:\/\/heisbudi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=189"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/heisbudi.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=189"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/heisbudi.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=189"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}