cHttpServerResponse Response Object

Overview

cHttpServerResponse is used to build and send HTTP responses, supporting text, HTML, JSON, files, and other response types.

Response Methods

Text

Send plain text response.

Public Sub Text(Data As String)

Parameters:

• Data - Response text content

Example:

ctx.Response.Text "Hello, World!"

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Html

Send HTML response.

Public Sub Html(Data As String)

Parameters:

• Data - HTML content

Example:

ctx.Response.Html "<h1>Hello</h1><p>Welcome to my site</p>"

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Json

Send JSON response.

Public Sub Json(Data As Variant, Optional Code As Long = -1, Optional msg As String, Optional Count As Long, Optional Whitespace As Variant)

Parameters:

• Data - Data to serialize to JSON (Dictionary, Array, etc.)
• Code - Status code (default -1 means no wrapper)
• msg - Message text
• Count - Total data count (for pagination)
• Whitespace - JSON formatting option

Example:

' Simple JSON
Dim data As New Dictionary
data("name") = "John"
data("age") = 25
ctx.Response.Json data

' Wrapped format (API standard response)
' Output: {"code": 0, "msg": "Success", "data": {...}, "count": 1}
ctx.Response.Json data, 0, "Success", 1

' Formatted output
ctx.Response.Json data, , , , True

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File

Send file response (with built-in ETag + 304 negotiated cache + lazy content cache).

Public Sub File(Path As String)

Parameters:

• Path - File path (relative to WebRoot)

Description:

• Auto-calculates ETag (based on file modification time + size) and sets ETag, Last-Modified response headers
• When browser sends If-None-Match that matches, returns 304 Not Modified (zero transfer)
• When file size ≤ MaxCacheFileSize, auto-adds to memory cache (lazy cache), subsequent access outputs from memory skipping disk I/O
• Files exceeding cache limit are still read from disk, but enjoy ETag/304 negotiated cache
• When file is updated on disk, ETag auto-changes and old cache auto-invalidates
• When path corresponds to a directory, auto-searches default documents (index.html etc); returns 403 if no default document found

Example:

' Send static file (auto with cache headers)
ctx.Response.File "/css/style.css"

' Access directory (auto-searches index.html)
ctx.Response.File "/"

' Large file (exceeds cache limit, always read from disk, but with ETag/304)
ctx.Response.File "/videos/demo.mp4"

Cache Mechanism Details:

Request → Calculate ETag (FSO metadata, no file content read)
  ├─> If-None-Match matches → 304 (zero transfer)
  ├─> Cache hit + ETag unchanged → Memory output (skip disk)
  ├─> Cache hit + ETag changed → Re-read + update cache
  └─> No cache → Disk read + lazy cache (only add if ≤ limit)

See Static File Serving - Cache Control

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Status Code Methods

State

Send custom status code response.

Public Sub State(Code As Long, Text As String, Optional Say As String = "Unknown status")

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State400

400 Bad Request.

Public Sub State400(Optional Say As String)

Example:

If Not IsValidParams Then
    ctx.Response.State400 "Invalid parameters"
End If

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State401

401 Unauthorized.

Public Sub State401(Optional Say As String)

Example:

If Not IsAuthenticated Then
    ctx.Response.State401 "Please login first"
End If

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State403

403 Forbidden.

Public Sub State403(Optional Say As String)

Example:

If Not HasPermission Then
    ctx.Response.State403 "No permission"
End If

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State404

404 Not Found.

Public Sub State404(Optional Say As String)

Example:

If Not UserExists(userId) Then
    ctx.Response.State404 "User not found"
End If

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State413

413 Payload Too Large.

Public Sub State413(Optional Say As String = "Request Entity Too Large")

Description: This status code is automatically returned when the request body exceeds the Server.MaxRequestSize limit. Can also be called manually.

Example:

' Check upload file size
If FileSize > MaxAllowedSize Then
    ctx.Response.State413 "File size exceeds limit"
End If

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State500

500 Internal Server Error.

Public Sub State500(Optional Say As String)

Example:

On Error GoTo ErrorHandler
' ... Business logic
Exit Sub

ErrorHandler:
    ctx.Response.State500 Err.Description

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State502

502 Gateway Error.

Public Sub State502(Optional Say As String)

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Configuration Properties

Header

Custom response header dictionary.

Public Header As New Dictionary

Example:

ctx.Response.Header("X-Custom-Header") = "CustomValue"
ctx.Response.Header("Cache-Control") = "no-cache"

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CharSet

Character encoding (default utf-8).

Public CharSet As String

Example:

ctx.Response.CharSet = "gb2312"

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ContentType

Content type.

Public ContentType As String

Example:

ctx.Response.ContentType = "application/xml"

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Status

HTTP status string.

Public Status As String

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JsonPackFieldNameCode

JSON wrapper field name - status code.

Public JsonPackFieldNameCode As String

Default: "code"

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JsonPackFieldNameMsg

JSON wrapper field name - message.

Public JsonPackFieldNameMsg As String

Default: "msg"

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JsonPackFieldNameData

JSON wrapper field name - data.

Public JsonPackFieldNameData As String

Default: "data"

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JsonPackFieldNameCount

JSON wrapper field name - total count.

Public JsonPackFieldNameCount As String

Default: "count"

Example:

' Custom JSON response field names
ctx.Response.JsonPackFieldNameCode = "status"
ctx.Response.JsonPackFieldNameMsg = "message"
ctx.Response.JsonPackFieldNameData = "result"
ctx.Response.JsonPackFieldNameCount = "total"

' Output: {"status": 0, "message": "OK", "result": {...}, "total": 10}
ctx.Response.Json data, 0, "OK", 10

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ASP-compatible Properties

Property	Description
Buffer	Output buffering
CacheControl	Cache control
CodePage	Code page
Expires	Expiration time
ExpiresAbsolute	Absolute expiration time
LCID	Locale identifier

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Last Updated: 2026-06-22