theandroidboy / allabouturi

All we want to know about URI (Uniform Resource Identifier).

URI definition :

• URI is a string of characters that identifies a resource.
• also URI is a refrence that points to the actuall data/resource.

formal format of URI:

Scheme:[//[user:password@]host[:port]] [/]path[?query][#fragment]

(anything between square the brackets is optional).

Breakdown of URI:

-so URI can be broken down into 5 parts given below.

• Scheme = scheme describe what type of resource we are pointing to (eg mailto ,geo,https).
• authority= authority is the part where we describe user name,password and host.
• path= path is further navigation to resource eg (/courses/ud851/lessons..)
• query= query is used to filter the resource.
• fragment= fragment contains data used by path of query.

Rules for building legitmate URI:

Identify which part of URI is optional

• Scheme = Not Optional
• authority = Optional
• path = Not Optional
• query = Optional
• fragment = Optional
• if authority is present than path should be preceded by "/" ,otherwise its optional.

inside Authority

• Authority has 3 parts
• UserName and password = Optional
• host = Not optional
• port= Optional
• "//" in start = Not Optional

inside "UserName and Password"

• userName =Not optional
• password=Not optional
• "UserName and Password" ends with "@" character.

inside "Port"

• port = Not Optional
• ":" in start = Not Optional

inside query

• query = Not Optional
• "?" in start = Not Optional

inside fragment

• fragment = Not Optional
• "#" in start = Not Optional

Some example types

• Content URI , has scheme content ,A content URI is a URI that identifies data in a provider .
• formal format

content://authority/path/id

• content://user_dictionary/words

• geo URI

• formal formate

  geo:latitude,longitude?z=level

• geo:0,0?q=Antwarp,Belgium & Z=10

• geo URI has scheme geo:

• in above URI example geo is scheme ,geo scheme describes that the resource/data type to which this URI points is a physical location.

• in above example scheme geo: is followed by path 0,0 . 0,0 is latitude and longitude .its 0,0 because according to rules if

• we decribe a string address than lat and long should be 0,0.

• their is not authority in above example because we don't need it also authority is optional.

  Are geo URI and Content URI legitmate URI's ?

• lets find out

• general URI format

  Scheme:[//[user:password@]host[:port]] [/]path[?query][#fragment]

• content URI format

  content://authority/path/id

• content URI exampe

  content://user_dictionary/words

• geo URI format

  geo:latitude,longitude?z=level

• geo URI example

  geo:0,0?q=Antwarp,Belgium & Z=10

• so content URI has scheme ,content authority , path so its legitmate as we know scheme and path are must and it has both.

• and geo URI is also legitmate as it has scheme geo, path, query and as we know scheme and path are must and it has both.

Conclusion

For content provider we only need to worry about Content URI ,as it is used to get data from content provider.