OP-003: Write bytes to a caller-supplied path

WriteFile is invoked over the FileService route on SAIF.Services.WCF.Services.FileService; this page documents the process end to end, from route dispatch to the message the caller receives.

Field	Value
Operation ID	OP-003
Trigger	Caller invokes WriteFile over the FileService route, or FaxService/ImagingService constructs a FileService internally and calls WriteFile directly.
Entry operation	WriteFile
Owning component	SAIF.Services.WCF.Services.FileService.WriteFile
Inputs	Request message parts listed below
Outputs	No response payload (void)
Failure behavior	Generic SOAP fault, per Faults and error pipeline

Request and response

Direction	Element	Type	Declared in	Notes
Request	path	string	BCL (System)	Destination filesystem path; not validated or constrained. (Yes)
Request	bytes	byte[]	BCL (System)	Content to write at path. (Yes)
Response	void	void	n/a (void)	Not applicable — the operation returns no value.

Steps

1. Call File.WriteAllBytes(path, bytes) directly against the caller-supplied path with no validation, canonicalization, containment check, or authorization (BR-WCF-004); a pre-existing file at path is overwritten.
2. On failure: a filesystem exception is logged by the installed error handler and surfaced to the caller as a generic SOAP fault with exception detail included.
3. Return.

Process flow

The following diagram visualizes this process's control flow.

flowchart TD
    A["Write bytes to caller-supplied path"]
    B["Return."]
    A --> B

Transaction and side effects

Aspect	Finding
Unit of work	None
Commit point	Not applicable
Records written	None
Downstream calls	None
Shared state touched	None
Repeat-call behavior	Overwrites the target file on every call

Logging

Surface	Written content
ErrorLogErrorHandler → LogService	Failure-path exception logging only, carrying method signature, calling user and exception detail; see Faults and error pipeline

Faults and error handling

Failure	Fault type the caller receives	Produced by	Source
Filesystem exception	Generic SOAP fault	The ErrorLogErrorHandler installed by [LogErrorBehavior]	src/WCF/SAIF.Services.WCF.Host/Services/FileService.cs

Authorization

Requirement	Enforced by	Source	Applies to
None in code	IIS authentication on the deployment (see Activation and hosting)	src/WCF/SAIF.Services.WCF.Host/Services/FileService.cs	This operation

Related documentation

• Index
• Overview
• Architecture
• Activation and hosting
• Operations
• Faults and error pipeline
• Authentication and authorization
• Dependencies
• Configuration
• Operations and processes
• Business rules
• Data model
• Operational runbook
• Tech debt

Note: Statements marked with * were inferred from code structure, naming conventions, or contextual evidence where direct confirmation was not available in source artifacts. Statements marked with ** could not be confirmed; treat as unknown until verified.

Sources

• src/WCF/SAIF.Services.WCF.Host/Services/FileService.cs