CouchDB HTTP API

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To communicate with CouchDB in order to retrieve data from the database, to store data into the database, to view the stored documents and to format the documents stored in a database, the HTTP requests are used. The input data and output data structures, for any operation in CouchDB, are in the form of JavaScript Object Notation (JSON) object.

 

HTTP Request Formats:

To communicate with CouchDB different request formats of HTTP Protocol are used, including:

REQUEST FORMAT USES
GET ●      To get static items.

●      To get statistical information in the form of JSON documents.

●      To get database documents and configuration.
HEAD ●      To get the HTTP header of a GET request without the body of the response.
POST ●      To set values.

●      To upload documents.

●      To set document values.

●      To start certain administration commands.
PUT ●      To create new Objects, Databases, Documents, Views and Design documents.
DELETE ●      To delete Documents, Views and Design documents.
COPY ●      To copy documents and objects.

 

HTTP Request Headers:

To get the right format and encoding, sending HTTP request headers along with the request is a must while sending the request to the CouchDB server. There are mainly two types of HTTP request headers. These are:

Content-type:

  • Used to specify the content type of the data to be sent to the server along with the request.
  • The type of content sent is mostly MIME type or JSON (application/JSON).
  • Highly recommended.

Accept:

  • Used to specify the list of data types that client can understand to the server.
  • The server thus sends its response using the specified data types. A list of MIME data types, separated by colons can be sent.
  • Using Accept in queries is not required in CouchDB.
  • But to ensure that the data returned can be processed by the client, this request header is highly recommended.

 

HTTP Response Headers:

The HTTP response headers are used to get information about the content sent by the server as a response as they itself are a type of response sent by the server. There are mainly four types of HTTP Response headers. These are:

Content-type:

  • Used to define the MIME type of the data sent by the server which is text/plain for most requests.

Cache-control:

  • Used to suggest the client about treating the information sent by the server.
  • If must-revalidate is returned, then the information should be revalidated if possible.

Content-length:

  • Used to retrieve the length of the content sent by the server.
  • It retrieves the length in bytes.

Etag:

  • Used to display the revision for a document or a view.

 

Status Codes of HTTP Headers:

STATUS CODE DESCRIPTION
200 – OK Generated when a request completed successfully.
201 – Created Generated when a document is created.
202 – Accepted Generated when a request is accepted.
404 – Not Found Issued when the server is unable to find the requested content.
405 – Resource Not Allowed Issued when the http request type used is invalid.
409 – Conflict Issued whenever there is any update conflict.
415 – Bad Content Type To specify that the requested content type is not supported by the server.
500 – Internal Server Error Issued whenever the invalid data is sent as request.

 

 

HTTP URL paths to interact with database:

URL USES
PUT /db To create a new database.
GET /db To get the information about the existing database.
PUT/db/document To create a document/update an existing document.
GET /db/document To get a document from the specified database.
DELETE /db/document To delete a document from the specified database.
GET/db/_design/design-doc To get the definition of a design document.
GET /db/_design/designdoc/_view/view-name To access the view, view-name of a design document.