UploadFileChunk API

Uploads a single binary chunk to a server-side upload handler as part of a chunked large-file upload workflow. Each chunk is verified against its CRC32 checksum before being appended. When lastChunk=true, the handler is marked as complete and ready for finalization.

Endpoint

/srv.asmx/UploadFileChunk

Methods

GET /srv.asmx/UploadFileChunk?authenticationTicket=...&uploadHandler=...&fileChunk=...&chunkHEXCRC=...&lastChunk=...
POST /srv.asmx/UploadFileChunk (form data — recommended for binary content)
SOAP Action: http://tempuri.org/UploadFileChunk

Parameters

Parameter	Type	Required	Description
`authenticationTicket`	string	Yes	Authentication ticket obtained from `AuthenticateUser`.
`uploadHandler`	string (GUID)	Yes	The upload handler GUID returned by `CreateUploadHandler`.
`fileChunk`	byte[]	Yes	The binary chunk data, encoded as Base64 when sent over HTTP. The recommended chunk size is returned by `CreateUploadHandler` (256 KB minimum, 32 MB maximum).
`chunkHEXCRC`	string	Yes	The CRC32 checksum of this chunk, expressed as a hexadecimal string (e.g. `A3F2B1C0`). The server verifies the checksum before appending the chunk.
`lastChunk`	bool	Yes	`true` if this is the final chunk of the file. `false` for all intermediate chunks. Setting `true` marks the handler as ready for finalization.

Chunked Upload Workflow

1. CreateUploadHandler  → returns UploadHandler GUID + recommended ChunkSize
2. UploadFileChunk      → upload chunk 1 (lastChunk=false)
3. UploadFileChunk      → upload chunk 2 (lastChunk=false)
   ...
N. UploadFileChunk      → upload last chunk (lastChunk=true)
N+1. UploadDocumentWithHandler[X] → finalize and create the document

Response

Success Response (non-final chunk)

<root success="true" tryagain="false" />

Success Response (final chunk)

<root success="true" tryagain="false" />

Checksum Mismatch (retry this chunk)

<root success="true" tryagain="true" />

When tryagain="true" is returned, the chunk was NOT appended — resend the same chunk.

Error Response

<root success="false" error="Invalid upload handler." />

Required Permissions

The calling user must be authenticated. The handler must have been created by the same authenticated session.

Example

POST Request (chunk upload)

POST /srv.asmx/UploadFileChunk HTTP/1.1
Content-Type: multipart/form-data; boundary=----FormBoundary

------FormBoundary
Content-Disposition: form-data; name="authenticationTicket"

3f2504e0-4f89-11d3-9a0c-0305e82c3301
------FormBoundary
Content-Disposition: form-data; name="uploadHandler"

a1b2c3d4-e5f6-7890-abcd-ef1234567890
------FormBoundary
Content-Disposition: form-data; name="fileChunk"; filename="chunk"
Content-Type: application/octet-stream

[binary chunk bytes]
------FormBoundary
Content-Disposition: form-data; name="chunkHEXCRC"

A3F2B1C0
------FormBoundary
Content-Disposition: form-data; name="lastChunk"

false
------FormBoundary--

Notes

Always check the tryagain attribute in the response. If tryagain="true", the chunk checksum did not match — resend the same chunk without advancing.
The recommended chunk size is returned by CreateUploadHandler and is between 256 KB and 32 MB.
Chunk sizes below 256 KB are automatically raised to 256 KB by the server.
CRC32 is computed over the raw binary chunk bytes before Base64 encoding.

CreateUploadHandler - Create the upload handler before calling this API
UploadDocumentWithHandler - Finalize the upload after all chunks are sent
UploadDocumentWithHandler3 - Finalize with XML parameters
DeleteUploadHandler - Discard the handler without creating a document
DownloadFileChunk - Download a file in chunks

Error Codes

Error	Description
`[900] Authentication failed`	Invalid or missing authentication ticket.
`[901] Session expired or Invalid ticket`	The ticket has expired or does not exist.
`Invalid upload handler.`	The GUID is not a valid GUID format.
Handler not found / expired	The handler file does not exist — it may have expired or been deleted.
`tryagain="true"`	Chunk checksum mismatch — resend the chunk.
`SystemError:...`	An unexpected server-side error occurred.

For detailed documentation visit: https://support.inforouter.com/api-docs/UploadFileChunk