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WRITE for named objects

If you WRITE a named object that already exists, the The existing object is overwritten with a new version if performing a WRITE of a named object that already exists.

WRITE that overwrites object

POST /bucket/photo.jpg HTTP/1.1
  Host: cluster.example.com
  User-Agent: Swarm Client/0.1
  Content-Length: 43402
  Expect: 100-continue
  Content-Type: image/jpeg 
  Content-Language: en/us, x-pig-latin 
  Content-Version: 42
  CRLF
  [ content ]

To prevent overwriting an existing object, include Include the If-None-Match: * request header to prevent overwriting an existing object.

• If Swarm WRITEs the named object if the named object does not exist, Swarm WRITEs the named object.

• If the named object exists, Swarm responds with a 412 Precondition Fail error if the named object exists.

WRITE that prevents overwriting

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Using PUT Create for named objects

If you want Add the scsp.allowPutCreate=True to the configuration parameters to configure Swarm to allow you to use using the HTTP PUT operation to create new named objects, add the scsp.allowPutCreate=True to your configuration parameters. You . The putcreate query argument can also enable it using the putcreate query argument.

Preventing overwriting: If-None-Match

In contrast to an unnamed object, if you WRITE a named object that already exists, the existing object is overwritten with a new version . To prevent overwriting an existing object, include if performing a WRITE of a named object that already exists. Include the If-None-Match: * request header to prevent overwriting an existing object.

• If Swarm WRITEs the named object if the named object does not exist, Swarm WRITEs the named object.

• If the named object exists, Swarm responds with a 412 Precondition Fail error if the named object exists.

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POST / HTTP/1.1 
  Host: cluster.example.com 
  User-Agent:Swarm Client/0.1 
  Content-Length: 43402 
  Expect: 100-continue
  Content-Type: image/jpeg
  Content-Language: en/us, x-pig-latin
  Content-Version: 42 
  CRLF 
  [ content ]

If you WRITE an unnamed object, a A new object is created and a new UUID is returned . If you WRITE an alias object, a if performing a WRITE of an unnamed object. A new object is created and a new alias UUID is returned if performing a WRITE of an alias object.

See WRITE for Unnamed Objects.

WRITE for alias objects

To Add alias=yes to create alias objects, add alias=yes:

WRITE for alias object

POST /?alias HTTP/1.1
  Host: cluster.example.com
  User-Agent: Swarm Client/0.1

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See Working with Large Objects.

WRITE for large files (Expect: 100-continue)

The Expect: 100-continue header tells the server that the client will wait after sending the header lines and before sending the content in the message body. The Swarm server can respond with a redirect or an error response.

• If the server is ready to store the contents, it The server returns a 100 Continue response, telling the client to transmit the entity body if the server is ready to store the contents. The client should needs to wait for a 100 Continue response from the server before proceeding to send the data.

• If the server is not ready, it The server sends a 413 Request entity too large error response and closes the connection if the server is not ready.

Swarm allows the client to omit the Expect: 100-continue header, sending all the content at once. In response, the The server reads and discards all data if it must respond with a redirect or error. For Swarm logs a warning for WRITE messages that include more than 65536 bytes, Swarm logs a warning:

Error if Expect header is missing

Please use Expect: 100-continue for large amounts of data.

If The cluster returns a 507 Insufficient Storage error if any node in the cluster does not have enough space to write the object, the cluster returns a 507 Insufficient Storage error.