What are post requests? How can I post data using Android when I have Google Volley implemented? Uploading images in HTTP using Android.

1. Uploading Images in
HTTP Using Android
By Ali Muzaffar
http://alimuzaffar.com

2. Posting Data over HTTP
When you post data in using HTTP, you have 2 content type
options:
- multipart/form-data
- application/x-www-form-urlencoded
Both formats transfer plain text over http.
The main difference is how the data is formatted.

3. Posting Data over HTTP
 The default format used when posting data is x-www-
form-urlencoded.
 There is a common misconception that form-data is the
default format.

4. Format of post using x-www…
 x-www-form-urlencoded posts data using a format
similar to (actually the same as) url parameters. This
is just a standard, the body can contain data in any
format as long as your backend is setup to handle it.
POST /my-api/customer/address/ HTTP/1.1
Host: my-server.com.au
Cache-Control: no-cache
Content-Type: application/x-www-form-urlencoded
NewShipping%5BfirstName%5D=Kiwi&NewShipping%5BlastName%5D=Jones&NewShipping%5Baddress1%5D=
Some+Place&NewShipping%5Baddress2%5D=In+New+Zealand&NewShipping%5Btown%5D=1842%2C+Surfdale
%2C+Waiheke+Island&NewShipping%5Bphone%5D=12345678&NewShipping%5Bcountry%5D=171&ShippingAd
dressOption=1&NewShipping%5Bgender%5D=male&NewShipping%5BbirthdayDay%5D=1&NewShipping%5Bbi
rthdayMonth%5D=2&NewShipping%5BbirthdayYear%5D=1942

5. Format of post using form-
data Form-data posts data using very structured data format. The body must be in this
format.
 It’s “multipart” because each section can have it’s own headers allowing for different
types of data to be transmitted.
POST /my-api/customer/address/ HTTP/1.1
Host: my-server.com.au
Cache-Control: no-cache
----WebKitFormBoundaryE19zNvXGzXaLvS5C
Content-Disposition: form-data; name="products[0][p]"
AT049AA59TWQ
----WebKitFormBoundaryE19zNvXGzXaLvS5C
Content-Disposition: form-data; name="products[0][image]”; Content-Type: image/png;
filename=“product_image.png”;
<base64 encoded image>
----WebKitFormBoundaryE19zNvXGzXaLvS5C
Content-Disposition: form-data; name="products[0][gift_wrap_num]"
0
----WebKitFormBoundaryE19zNvXGzXaLvS5C

6. Images and Password
 Base64 encoded.
 Plain HTTP username and password are base 64 encoded
and added to the headers.
 “username:password” is the format (similar to apache
htaccess.
 Key: Authorize
 Value: Basic <Base64>
 Images, by default are Base64 encoded in the form-data
format.
 Content-Type and filename can he optionally specified for
the “part” that contains the image.

7. Uploading Images Using
Volley
 Volley by default uses application/x-www-form-
urlencoded format.
 Certain services may require a multipart/form-data post.
 Simple MultipartRequest for Google Volley
 We fallback to using direct HTTP, but what do you do if
you’re using Volley?

8. Uploading images bypassing
Volley
 Reuse your HttpStack implementation, create a new
instance of HttpStack and use it to get your HttpClient.
 Use the HttpClient to build a multipart post.
 Example code here:
 https://gist.github.com/alphamu/7190a8ed0986b5fb8376

9. Thank you
 MultipartRequest for Google Volley
 https://gist.github.com/alphamu/684d8ae311d95831ce1c
 Sample SslHttpStack implementation and Uploading
images using it.
 https://gist.github.com/alphamu/7190a8ed0986b5fb8376
 Learn more about multipart messages:
 http://en.wikipedia.org/wiki/MIME#Multipart_message
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