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ef7478b30a00644c7853d75599642f0b9ba0b187
stegasoo/frontends/api/main.py
Aaron D. Lee ef7478b30a A whoooole lotta 4.0.x fixes.
2026-01-01 22:18:13 -05:00

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#!/usr/bin/env python3
"""
Stegasoo REST API (v4.0.0)
FastAPI-based REST API for steganography operations.
Supports both text messages and file embedding.
CHANGES in v4.0.0:
- Updated from v3.2.0 with no functional API changes
- Internal: JPEG normalization for jpegio compatibility
- Internal: Python 3.12 recommended
CHANGES in v3.2.0:
- Removed date dependency from all operations
- Renamed day_phrase → passphrase
- No date_str parameters needed
- Simplified API for asynchronous communications
NEW in v3.0: LSB and DCT embedding modes.
NEW in v3.0.1: DCT color mode and JPEG output format.
"""
import io
import sys
import base64
from pathlib import Path
from typing import Optional, Literal
from datetime import date
from fastapi import FastAPI, HTTPException, UploadFile, File, Form, Query
from fastapi.responses import Response, JSONResponse
from pydantic import BaseModel, Field
# Add parent to path for development
sys.path.insert(0, str(Path(__file__).parent.parent.parent / 'src'))
import stegasoo
from stegasoo import (
encode, decode, generate_credentials,
validate_image,
__version__,
StegasooError, DecryptionError, CapacityError,
has_argon2,
FilePayload,
MAX_FILE_PAYLOAD_SIZE,
# Embedding modes
EMBED_MODE_LSB,
EMBED_MODE_DCT,
EMBED_MODE_AUTO,
has_dct_support,
compare_modes,
will_fit_by_mode,
calculate_capacity_by_mode,
)
from stegasoo.constants import (
MIN_PIN_LENGTH, MAX_PIN_LENGTH,
MIN_PASSPHRASE_WORDS, MAX_PASSPHRASE_WORDS,
DEFAULT_PASSPHRASE_WORDS,
VALID_RSA_SIZES,
)
# QR Code utilities
try:
from stegasoo.qr_utils import (
extract_key_from_qr,
has_qr_read,
)
HAS_QR_READ = has_qr_read()
except ImportError:
HAS_QR_READ = False
extract_key_from_qr = None
# ============================================================================
# FASTAPI APP
# ============================================================================
app = FastAPI(
title="Stegasoo API",
description="""
Secure steganography with hybrid authentication. Supports text messages and file embedding.
## Version 4.0.0 Changes
- **Python 3.12 recommended** - jpegio compatibility improvements
- **JPEG normalization** - Handles quality=100 images automatically
## Version 3.2.0 Changes
- **No date parameters needed** - Encode and decode anytime without tracking dates
- **Single passphrase** - No daily rotation, just use your passphrase
- **True asynchronous communications** - Perfect for dead drops and delayed delivery
## Embedding Modes (v3.0)
- **LSB mode** (default): Spatial LSB embedding, full color output, higher capacity
- **DCT mode**: Frequency domain embedding, ~20% capacity, better stealth
## DCT Options (v3.0.1)
- **dct_color_mode**: 'grayscale' (default) or 'color' (preserves original colors)
- **dct_output_format**: 'png' (lossless) or 'jpeg' (smaller, more natural)
Use the `/modes` endpoint to check availability and `/compare` to compare capacities.
""",
version=__version__,
docs_url="/docs",
redoc_url="/redoc",
)
# ============================================================================
# TYPE ALIASES
# ============================================================================
EmbedModeType = Literal["lsb", "dct"]
ExtractModeType = Literal["auto", "lsb", "dct"]
DctColorModeType = Literal["grayscale", "color"]
DctOutputFormatType = Literal["png", "jpeg"]
# ============================================================================
# MODELS
# ============================================================================
class GenerateRequest(BaseModel):
use_pin: bool = True
use_rsa: bool = False
pin_length: int = Field(default=6, ge=MIN_PIN_LENGTH, le=MAX_PIN_LENGTH)
rsa_bits: int = Field(default=2048)
words_per_passphrase: int = Field(
default=DEFAULT_PASSPHRASE_WORDS,
ge=MIN_PASSPHRASE_WORDS,
le=MAX_PASSPHRASE_WORDS,
description="Words per passphrase (v3.2.0: default increased to 4)"
)
class GenerateResponse(BaseModel):
passphrase: str = Field(description="Single passphrase (v3.2.0: no daily rotation)")
pin: Optional[str] = None
rsa_key_pem: Optional[str] = None
entropy: dict[str, int]
# Legacy field for compatibility
phrases: Optional[dict[str, str]] = Field(
default=None,
description="Deprecated: Use 'passphrase' instead"
)
class EncodeRequest(BaseModel):
message: str
reference_photo_base64: str
carrier_image_base64: str
passphrase: str = Field(description="Passphrase (v3.2.0: renamed from day_phrase)")
pin: str = ""
rsa_key_base64: Optional[str] = None
rsa_password: Optional[str] = None
# date_str removed in v3.2.0
embed_mode: EmbedModeType = Field(
default="lsb",
description="Embedding mode: 'lsb' (default, color) or 'dct' (requires scipy)"
)
# NEW in v3.0.1
dct_output_format: DctOutputFormatType = Field(
default="png",
description="DCT output format: 'png' (lossless) or 'jpeg' (smaller). Only applies to DCT mode."
)
dct_color_mode: DctColorModeType = Field(
default="grayscale",
description="DCT color mode: 'grayscale' (default) or 'color' (preserves colors). Only applies to DCT mode."
)
class EncodeFileRequest(BaseModel):
"""Request for embedding a file (base64-encoded)."""
file_data_base64: str
filename: str
mime_type: Optional[str] = None
reference_photo_base64: str
carrier_image_base64: str
passphrase: str = Field(description="Passphrase (v3.2.0: renamed from day_phrase)")
pin: str = ""
rsa_key_base64: Optional[str] = None
rsa_password: Optional[str] = None
# date_str removed in v3.2.0
embed_mode: EmbedModeType = Field(
default="lsb",
description="Embedding mode: 'lsb' (default, color) or 'dct' (requires scipy)"
)
# NEW in v3.0.1
dct_output_format: DctOutputFormatType = Field(
default="png",
description="DCT output format: 'png' (lossless) or 'jpeg' (smaller). Only applies to DCT mode."
)
dct_color_mode: DctColorModeType = Field(
default="grayscale",
description="DCT color mode: 'grayscale' (default) or 'color' (preserves colors). Only applies to DCT mode."
)
class EncodeResponse(BaseModel):
stego_image_base64: str
filename: str
capacity_used_percent: float
embed_mode: str = Field(description="Embedding mode used: 'lsb' or 'dct'")
# NEW in v3.0.1
output_format: str = Field(
default="png",
description="Output format: 'png' or 'jpeg' (for DCT mode)"
)
color_mode: str = Field(
default="color",
description="Color mode: 'color' (LSB/DCT color) or 'grayscale' (DCT grayscale)"
)
# Legacy fields (v3.2.0: no longer used in crypto)
date_used: Optional[str] = Field(
default=None,
description="Deprecated: Date no longer used in v3.2.0"
)
day_of_week: Optional[str] = Field(
default=None,
description="Deprecated: Date no longer used in v3.2.0"
)
class DecodeRequest(BaseModel):
stego_image_base64: str
reference_photo_base64: str
passphrase: str = Field(description="Passphrase (v3.2.0: renamed from day_phrase)")
pin: str = ""
rsa_key_base64: Optional[str] = None
rsa_password: Optional[str] = None
embed_mode: ExtractModeType = Field(
default="auto",
description="Extraction mode: 'auto' (default), 'lsb', or 'dct'"
)
class DecodeResponse(BaseModel):
"""Response for decode - can be text or file."""
payload_type: str # 'text' or 'file'
message: Optional[str] = None # For text
file_data_base64: Optional[str] = None # For file (base64-encoded)
filename: Optional[str] = None # For file
mime_type: Optional[str] = None # For file
class ModeCapacity(BaseModel):
"""Capacity info for a single mode."""
capacity_bytes: int
capacity_kb: float
available: bool
output_format: str
class ImageInfoResponse(BaseModel):
width: int
height: int
pixels: int
capacity_bytes: int = Field(description="LSB mode capacity (for backwards compatibility)")
capacity_kb: int = Field(description="LSB mode capacity in KB")
# NEW in v3.0
modes: Optional[dict[str, ModeCapacity]] = Field(
default=None,
description="Capacity by embedding mode (v3.0+)"
)
class CompareModesRequest(BaseModel):
"""Request for comparing embedding modes."""
carrier_image_base64: str
payload_size: Optional[int] = Field(
default=None,
description="Optional payload size to check if it fits"
)
class CompareModesResponse(BaseModel):
"""Response comparing LSB and DCT modes."""
width: int
height: int
lsb: dict
dct: dict
payload_check: Optional[dict] = None
recommendation: str
class DctModeInfo(BaseModel):
"""Detailed DCT mode information."""
available: bool
name: str
description: str
output_formats: list[str]
color_modes: list[str]
capacity_ratio: str
requires: str
class ModesResponse(BaseModel):
"""Response showing available embedding modes."""
lsb: dict
dct: DctModeInfo
class StatusResponse(BaseModel):
version: str
has_argon2: bool
has_qrcode_read: bool
has_dct: bool
max_payload_kb: int
available_modes: list[str]
# NEW in v3.0.1
dct_features: Optional[dict] = Field(
default=None,
description="DCT mode features (v3.0.1+)"
)
# NEW in v3.2.0
breaking_changes: dict = Field(
description="v3.2.0 breaking changes"
)
class QrExtractResponse(BaseModel):
success: bool
key_pem: Optional[str] = None
error: Optional[str] = None
class WillFitRequest(BaseModel):
"""Request to check if payload will fit."""
carrier_image_base64: str
payload_size: int
embed_mode: EmbedModeType = "lsb"
class WillFitResponse(BaseModel):
"""Response for will_fit check."""
fits: bool
payload_size: int
capacity: int
usage_percent: float
headroom: int
mode: str
class ErrorResponse(BaseModel):
error: str
detail: Optional[str] = None
# ============================================================================
# ROUTES - STATUS & INFO
# ============================================================================
@app.get("/", response_model=StatusResponse)
async def root():
"""Get API status and configuration."""
available_modes = ["lsb"]
dct_features = None
if has_dct_support():
available_modes.append("dct")
dct_features = {
"output_formats": ["png", "jpeg"],
"color_modes": ["grayscale", "color"],
"default_output_format": "png",
"default_color_mode": "grayscale",
}
return StatusResponse(
version=__version__,
has_argon2=has_argon2(),
has_qrcode_read=HAS_QR_READ,
has_dct=has_dct_support(),
max_payload_kb=MAX_FILE_PAYLOAD_SIZE // 1024,
available_modes=available_modes,
dct_features=dct_features,
breaking_changes={
"date_removed": "No date_str parameter needed - encode/decode anytime",
"passphrase_renamed": "day_phrase → passphrase (single passphrase, no daily rotation)",
"format_version": 4,
"backward_compatible": False,
}
)
@app.get("/modes", response_model=ModesResponse)
async def api_modes():
"""
Get available embedding modes and their status.
NEW in v3.0: Shows LSB and DCT mode availability.
NEW in v3.0.1: Shows DCT color modes and output formats.
"""
return ModesResponse(
lsb={
"available": True,
"name": "Spatial LSB",
"description": "Embed in pixel LSBs, outputs PNG/BMP",
"output_format": "PNG (color)",
"capacity_ratio": "100%",
},
dct=DctModeInfo(
available=has_dct_support(),
name="DCT Domain",
description="Embed in DCT coefficients, frequency domain steganography",
output_formats=["png", "jpeg"],
color_modes=["grayscale", "color"],
capacity_ratio="~20% of LSB",
requires="scipy",
)
)
@app.post("/compare", response_model=CompareModesResponse)
async def api_compare_modes(request: CompareModesRequest):
"""
Compare LSB and DCT embedding modes for a carrier image.
NEW in v3.0: Returns capacity for both modes and recommendation.
Optionally checks if a specific payload size would fit.
"""
try:
carrier = base64.b64decode(request.carrier_image_base64)
comparison = compare_modes(carrier)
response = CompareModesResponse(
width=comparison['width'],
height=comparison['height'],
lsb={
"capacity_bytes": comparison['lsb']['capacity_bytes'],
"capacity_kb": round(comparison['lsb']['capacity_kb'], 1),
"available": True,
"output_format": comparison['lsb']['output'],
},
dct={
"capacity_bytes": comparison['dct']['capacity_bytes'],
"capacity_kb": round(comparison['dct']['capacity_kb'], 1),
"available": comparison['dct']['available'],
"output_formats": ["png", "jpeg"],
"color_modes": ["grayscale", "color"],
"ratio_vs_lsb_percent": round(comparison['dct']['ratio_vs_lsb'], 1),
},
recommendation="lsb" if not comparison['dct']['available'] else "dct for stealth, lsb for capacity"
)
if request.payload_size:
fits_lsb = request.payload_size <= comparison['lsb']['capacity_bytes']
fits_dct = request.payload_size <= comparison['dct']['capacity_bytes']
response.payload_check = {
"size_bytes": request.payload_size,
"fits_lsb": fits_lsb,
"fits_dct": fits_dct,
}
# Update recommendation based on payload
if fits_dct and comparison['dct']['available']:
response.recommendation = "dct (payload fits, better stealth)"
elif fits_lsb:
response.recommendation = "lsb (payload too large for dct)"
else:
response.recommendation = "none (payload too large for both modes)"
return response
except Exception as e:
raise HTTPException(500, str(e))
@app.post("/will-fit", response_model=WillFitResponse)
async def api_will_fit(request: WillFitRequest):
"""
Check if a payload of given size will fit in the carrier image.
NEW in v3.0: Supports both LSB and DCT modes.
"""
try:
# Validate mode
if request.embed_mode == "dct" and not has_dct_support():
raise HTTPException(400, "DCT mode requires scipy. Install with: pip install scipy")
carrier = base64.b64decode(request.carrier_image_base64)
result = will_fit_by_mode(request.payload_size, carrier, embed_mode=request.embed_mode)
return WillFitResponse(
fits=result['fits'],
payload_size=result['payload_size'],
capacity=result['capacity'],
usage_percent=round(result['usage_percent'], 1),
headroom=result['headroom'],
mode=request.embed_mode
)
except HTTPException:
raise
except Exception as e:
raise HTTPException(500, str(e))
# ============================================================================
# ROUTES - QR CODE
# ============================================================================
@app.post("/extract-key-from-qr", response_model=QrExtractResponse)
async def api_extract_key_from_qr(
qr_image: UploadFile = File(..., description="QR code image containing RSA key")
):
"""
Extract RSA key from a QR code image.
Supports both compressed (STEGASOO-Z: prefix) and uncompressed keys.
Returns the PEM-encoded key if found.
"""
if not HAS_QR_READ:
raise HTTPException(
501,
"QR code reading not available. Install pyzbar and libzbar."
)
try:
image_data = await qr_image.read()
key_pem = extract_key_from_qr(image_data)
if key_pem:
return QrExtractResponse(success=True, key_pem=key_pem)
else:
return QrExtractResponse(
success=False,
error="No valid RSA key found in QR code"
)
except Exception as e:
return QrExtractResponse(success=False, error=str(e))
# ============================================================================
# ROUTES - GENERATE
# ============================================================================
@app.post("/generate", response_model=GenerateResponse)
async def api_generate(request: GenerateRequest):
"""
Generate credentials for encoding/decoding.
At least one of use_pin or use_rsa must be True.
v3.2.0: Generates single passphrase (no daily rotation).
Default increased to 4 words for better security.
"""
if not request.use_pin and not request.use_rsa:
raise HTTPException(400, "Must enable at least one of use_pin or use_rsa")
if request.rsa_bits not in VALID_RSA_SIZES:
raise HTTPException(400, f"rsa_bits must be one of {VALID_RSA_SIZES}")
try:
# v3.2.0: Call with passphrase_words parameter
creds = generate_credentials(
use_pin=request.use_pin,
use_rsa=request.use_rsa,
pin_length=request.pin_length,
rsa_bits=request.rsa_bits,
passphrase_words=request.words_per_passphrase, # Map API field to library parameter
)
return GenerateResponse(
passphrase=creds.passphrase, # v3.2.0: Single passphrase
pin=creds.pin,
rsa_key_pem=creds.rsa_key_pem,
entropy={
"passphrase": creds.passphrase_entropy,
"pin": creds.pin_entropy,
"rsa": creds.rsa_entropy,
"total": creds.total_entropy
},
phrases=None # Legacy field removed
)
except Exception as e:
raise HTTPException(500, str(e))
# ============================================================================
# HELPER FUNCTION FOR DCT PARAMETERS
# ============================================================================
def _get_dct_params(embed_mode: str, dct_output_format: str, dct_color_mode: str) -> dict:
"""
Get DCT-specific parameters if DCT mode is selected.
Returns kwargs to pass to encode().
"""
if embed_mode != "dct":
return {}
return {
"dct_output_format": dct_output_format,
"dct_color_mode": dct_color_mode,
}
def _get_output_info(embed_mode: str, dct_output_format: str, dct_color_mode: str) -> tuple:
"""
Get output format and color mode strings for response.
Returns (output_format, color_mode, mime_type).
"""
if embed_mode == "dct":
output_format = dct_output_format
color_mode = dct_color_mode
mime_type = "image/jpeg" if dct_output_format == "jpeg" else "image/png"
else:
output_format = "png"
color_mode = "color"
mime_type = "image/png"
return output_format, color_mode, mime_type
# ============================================================================
# ROUTES - ENCODE (JSON)
# ============================================================================
@app.post("/encode", response_model=EncodeResponse)
async def api_encode(request: EncodeRequest):
"""
Encode a text message into an image.
Images must be base64-encoded. Returns base64-encoded stego image.
v3.2.0: No date_str parameter needed - encode anytime!
NEW in v3.0: Supports embed_mode parameter ('lsb' or 'dct').
NEW in v3.0.1: Supports dct_output_format ('png' or 'jpeg') and dct_color_mode ('grayscale' or 'color').
"""
# Validate mode
if request.embed_mode == "dct" and not has_dct_support():
raise HTTPException(400, "DCT mode requires scipy. Install with: pip install scipy")
try:
ref_photo = base64.b64decode(request.reference_photo_base64)
carrier = base64.b64decode(request.carrier_image_base64)
rsa_key = base64.b64decode(request.rsa_key_base64) if request.rsa_key_base64 else None
# Get DCT parameters
dct_params = _get_dct_params(
request.embed_mode,
request.dct_output_format,
request.dct_color_mode
)
# v3.2.0: No date_str parameter
result = encode(
message=request.message,
reference_photo=ref_photo,
carrier_image=carrier,
passphrase=request.passphrase, # v3.2.0: Renamed from day_phrase
pin=request.pin,
rsa_key_data=rsa_key,
rsa_password=request.rsa_password,
# date_str removed in v3.2.0
embed_mode=request.embed_mode,
**dct_params,
)
stego_b64 = base64.b64encode(result.stego_image).decode('utf-8')
output_format, color_mode, _ = _get_output_info(
request.embed_mode,
request.dct_output_format,
request.dct_color_mode
)
return EncodeResponse(
stego_image_base64=stego_b64,
filename=result.filename,
capacity_used_percent=result.capacity_percent,
embed_mode=request.embed_mode,
output_format=output_format,
color_mode=color_mode,
date_used=None, # v3.2.0: No longer used
day_of_week=None, # v3.2.0: No longer used
)
except CapacityError as e:
raise HTTPException(400, str(e))
except StegasooError as e:
raise HTTPException(400, str(e))
except Exception as e:
raise HTTPException(500, str(e))
@app.post("/encode/file", response_model=EncodeResponse)
async def api_encode_file(request: EncodeFileRequest):
"""
Encode a file into an image (JSON with base64).
File data must be base64-encoded.
v3.2.0: No date_str parameter needed - encode anytime!
NEW in v3.0: Supports embed_mode parameter ('lsb' or 'dct').
NEW in v3.0.1: Supports dct_output_format and dct_color_mode.
"""
# Validate mode
if request.embed_mode == "dct" and not has_dct_support():
raise HTTPException(400, "DCT mode requires scipy. Install with: pip install scipy")
try:
file_data = base64.b64decode(request.file_data_base64)
ref_photo = base64.b64decode(request.reference_photo_base64)
carrier = base64.b64decode(request.carrier_image_base64)
rsa_key = base64.b64decode(request.rsa_key_base64) if request.rsa_key_base64 else None
payload = FilePayload(
data=file_data,
filename=request.filename,
mime_type=request.mime_type
)
# Get DCT parameters
dct_params = _get_dct_params(
request.embed_mode,
request.dct_output_format,
request.dct_color_mode
)
# v3.2.0: No date_str parameter
result = encode(
message=payload,
reference_photo=ref_photo,
carrier_image=carrier,
passphrase=request.passphrase, # v3.2.0: Renamed from day_phrase
pin=request.pin,
rsa_key_data=rsa_key,
rsa_password=request.rsa_password,
# date_str removed in v3.2.0
embed_mode=request.embed_mode,
**dct_params,
)
stego_b64 = base64.b64encode(result.stego_image).decode('utf-8')
output_format, color_mode, _ = _get_output_info(
request.embed_mode,
request.dct_output_format,
request.dct_color_mode
)
return EncodeResponse(
stego_image_base64=stego_b64,
filename=result.filename,
capacity_used_percent=result.capacity_percent,
embed_mode=request.embed_mode,
output_format=output_format,
color_mode=color_mode,
date_used=None, # v3.2.0: No longer used
day_of_week=None, # v3.2.0: No longer used
)
except CapacityError as e:
raise HTTPException(400, str(e))
except StegasooError as e:
raise HTTPException(400, str(e))
except Exception as e:
raise HTTPException(500, str(e))
# ============================================================================
# ROUTES - DECODE (JSON)
# ============================================================================
@app.post("/decode", response_model=DecodeResponse)
async def api_decode(request: DecodeRequest):
"""
Decode a message or file from a stego image.
Returns payload_type to indicate if result is text or file.
v3.2.0: No date_str parameter needed - decode anytime!
NEW in v3.0: Supports embed_mode parameter ('auto', 'lsb', or 'dct').
With 'auto' (default), tries LSB first then DCT.
Note: Extraction works regardless of whether the image was created with
color mode or grayscale mode - both use the same Y channel for data.
"""
# Validate mode
if request.embed_mode == "dct" and not has_dct_support():
raise HTTPException(400, "DCT mode requires scipy. Install with: pip install scipy")
try:
stego = base64.b64decode(request.stego_image_base64)
ref_photo = base64.b64decode(request.reference_photo_base64)
rsa_key = base64.b64decode(request.rsa_key_base64) if request.rsa_key_base64 else None
# v3.2.0: No date_str parameter
result = decode(
stego_image=stego,
reference_photo=ref_photo,
passphrase=request.passphrase, # v3.2.0: Renamed from day_phrase
pin=request.pin,
rsa_key_data=rsa_key,
rsa_password=request.rsa_password,
embed_mode=request.embed_mode,
)
if result.is_file:
return DecodeResponse(
payload_type='file',
file_data_base64=base64.b64encode(result.file_data).decode('utf-8'),
filename=result.filename,
mime_type=result.mime_type
)
else:
return DecodeResponse(
payload_type='text',
message=result.message
)
except DecryptionError as e:
raise HTTPException(401, "Decryption failed. Check credentials.")
except StegasooError as e:
raise HTTPException(400, str(e))
except Exception as e:
raise HTTPException(500, str(e))
# ============================================================================
# ROUTES - ENCODE/DECODE (MULTIPART)
# ============================================================================
@app.post("/encode/multipart")
async def api_encode_multipart(
passphrase: str = Form(..., description="Passphrase (v3.2.0: renamed from day_phrase)"),
reference_photo: UploadFile = File(...),
carrier: UploadFile = File(...),
message: str = Form(""),
payload_file: Optional[UploadFile] = File(None),
pin: str = Form(""),
rsa_key: Optional[UploadFile] = File(None),
rsa_key_qr: Optional[UploadFile] = File(None),
rsa_password: str = Form(""),
# date_str removed in v3.2.0
embed_mode: str = Form("lsb"),
# NEW in v3.0.1
dct_output_format: str = Form("png"),
dct_color_mode: str = Form("grayscale"),
):
"""
Encode using multipart form data (file uploads).
Provide either 'message' (text) or 'payload_file' (binary file).
RSA key can be provided as 'rsa_key' (.pem file) or 'rsa_key_qr' (QR code image).
Returns the stego image directly with metadata headers.
v3.2.0: No date_str parameter needed - encode anytime!
NEW in v3.0: Supports embed_mode parameter ('lsb' or 'dct').
NEW in v3.0.1: Supports dct_output_format ('png' or 'jpeg') and dct_color_mode ('grayscale' or 'color').
"""
# Validate mode
if embed_mode not in ("lsb", "dct"):
raise HTTPException(400, "embed_mode must be 'lsb' or 'dct'")
if embed_mode == "dct" and not has_dct_support():
raise HTTPException(400, "DCT mode requires scipy. Install with: pip install scipy")
# Validate DCT options
if dct_output_format not in ("png", "jpeg"):
raise HTTPException(400, "dct_output_format must be 'png' or 'jpeg'")
if dct_color_mode not in ("grayscale", "color"):
raise HTTPException(400, "dct_color_mode must be 'grayscale' or 'color'")
try:
ref_data = await reference_photo.read()
carrier_data = await carrier.read()
# Handle RSA key from .pem file or QR code image
rsa_key_data = None
rsa_key_from_qr = False
if rsa_key and rsa_key.filename:
rsa_key_data = await rsa_key.read()
elif rsa_key_qr and rsa_key_qr.filename:
if not HAS_QR_READ:
raise HTTPException(
501,
"QR code reading not available. Install pyzbar and libzbar."
)
qr_image_data = await rsa_key_qr.read()
key_pem = extract_key_from_qr(qr_image_data)
if not key_pem:
raise HTTPException(400, "Could not extract RSA key from QR code image")
rsa_key_data = key_pem.encode('utf-8')
rsa_key_from_qr = True
# QR code keys are never password-protected
effective_password = None if rsa_key_from_qr else (rsa_password if rsa_password else None)
# Determine payload
if payload_file and payload_file.filename:
file_data = await payload_file.read()
payload = FilePayload(
data=file_data,
filename=payload_file.filename,
mime_type=payload_file.content_type
)
elif message:
payload = message
else:
raise HTTPException(400, "Must provide either 'message' or 'payload_file'")
# Get DCT parameters
dct_params = _get_dct_params(embed_mode, dct_output_format, dct_color_mode)
# v3.2.0: No date_str parameter
result = encode(
message=payload,
reference_photo=ref_data,
carrier_image=carrier_data,
passphrase=passphrase, # v3.2.0: Renamed from day_phrase
pin=pin,
rsa_key_data=rsa_key_data,
rsa_password=effective_password,
# date_str removed in v3.2.0
embed_mode=embed_mode,
**dct_params,
)
output_format, color_mode, mime_type = _get_output_info(
embed_mode, dct_output_format, dct_color_mode
)
return Response(
content=result.stego_image,
media_type=mime_type,
headers={
"Content-Disposition": f"attachment; filename={result.filename}",
"X-Stegasoo-Capacity-Percent": f"{result.capacity_percent:.1f}",
"X-Stegasoo-Embed-Mode": embed_mode,
"X-Stegasoo-Output-Format": output_format,
"X-Stegasoo-Color-Mode": color_mode,
"X-Stegasoo-Version": __version__,
}
)
except CapacityError as e:
raise HTTPException(400, str(e))
except StegasooError as e:
raise HTTPException(400, str(e))
except HTTPException:
raise
except Exception as e:
raise HTTPException(500, str(e))
@app.post("/decode/multipart", response_model=DecodeResponse)
async def api_decode_multipart(
passphrase: str = Form(..., description="Passphrase (v3.2.0: renamed from day_phrase)"),
reference_photo: UploadFile = File(...),
stego_image: UploadFile = File(...),
pin: str = Form(""),
rsa_key: Optional[UploadFile] = File(None),
rsa_key_qr: Optional[UploadFile] = File(None),
rsa_password: str = Form(""),
embed_mode: str = Form("auto"),
):
"""
Decode using multipart form data (file uploads).
RSA key can be provided as 'rsa_key' (.pem file) or 'rsa_key_qr' (QR code image).
Returns JSON with payload_type indicating text or file.
v3.2.0: No date_str parameter needed - decode anytime!
NEW in v3.0: Supports embed_mode parameter ('auto', 'lsb', or 'dct').
Note: Extraction works the same regardless of color mode used during encoding.
"""
# Validate mode
if embed_mode not in ("auto", "lsb", "dct"):
raise HTTPException(400, "embed_mode must be 'auto', 'lsb', or 'dct'")
if embed_mode == "dct" and not has_dct_support():
raise HTTPException(400, "DCT mode requires scipy. Install with: pip install scipy")
try:
ref_data = await reference_photo.read()
stego_data = await stego_image.read()
# Handle RSA key from .pem file or QR code image
rsa_key_data = None
rsa_key_from_qr = False
if rsa_key and rsa_key.filename:
rsa_key_data = await rsa_key.read()
elif rsa_key_qr and rsa_key_qr.filename:
if not HAS_QR_READ:
raise HTTPException(
501,
"QR code reading not available. Install pyzbar and libzbar."
)
qr_image_data = await rsa_key_qr.read()
key_pem = extract_key_from_qr(qr_image_data)
if not key_pem:
raise HTTPException(400, "Could not extract RSA key from QR code image")
rsa_key_data = key_pem.encode('utf-8')
rsa_key_from_qr = True
# QR code keys are never password-protected
effective_password = None if rsa_key_from_qr else (rsa_password if rsa_password else None)
# v3.2.0: No date_str parameter
result = decode(
stego_image=stego_data,
reference_photo=ref_data,
passphrase=passphrase, # v3.2.0: Renamed from day_phrase
pin=pin,
rsa_key_data=rsa_key_data,
rsa_password=effective_password,
embed_mode=embed_mode,
)
if result.is_file:
return DecodeResponse(
payload_type='file',
file_data_base64=base64.b64encode(result.file_data).decode('utf-8'),
filename=result.filename,
mime_type=result.mime_type
)
else:
return DecodeResponse(
payload_type='text',
message=result.message
)
except DecryptionError:
raise HTTPException(401, "Decryption failed. Check credentials.")
except StegasooError as e:
raise HTTPException(400, str(e))
except HTTPException:
raise
except Exception as e:
raise HTTPException(500, str(e))
# ============================================================================
# ROUTES - IMAGE INFO
# ============================================================================
@app.post("/image/info", response_model=ImageInfoResponse)
async def api_image_info(
image: UploadFile = File(...),
include_modes: bool = Query(True, description="Include capacity by mode (v3.0+)")
):
"""
Get information about an image's capacity.
NEW in v3.0: Optionally includes capacity for both LSB and DCT modes.
"""
try:
image_data = await image.read()
result = validate_image(image_data, check_size=False)
if not result.is_valid:
raise HTTPException(400, result.error_message)
capacity = calculate_capacity_by_mode(image_data, 'lsb')
response = ImageInfoResponse(
width=result.details['width'],
height=result.details['height'],
pixels=result.details['pixels'],
capacity_bytes=capacity,
capacity_kb=capacity // 1024
)
# NEW in v3.0 - include mode comparison
if include_modes:
comparison = compare_modes(image_data)
response.modes = {
"lsb": ModeCapacity(
capacity_bytes=comparison['lsb']['capacity_bytes'],
capacity_kb=round(comparison['lsb']['capacity_kb'], 1),
available=True,
output_format=comparison['lsb']['output'],
),
"dct": ModeCapacity(
capacity_bytes=comparison['dct']['capacity_bytes'],
capacity_kb=round(comparison['dct']['capacity_kb'], 1),
available=comparison['dct']['available'],
output_format="PNG/JPEG (grayscale or color)",
),
}
return response
except HTTPException:
raise
except Exception as e:
raise HTTPException(500, str(e))
# ============================================================================
# ERROR HANDLERS
# ============================================================================
@app.exception_handler(StegasooError)
async def stegasoo_error_handler(request, exc):
return JSONResponse(
status_code=400,
content={"error": type(exc).__name__, "detail": str(exc)}
)
# ============================================================================
# MAIN
# ============================================================================
if __name__ == '__main__':
import uvicorn
uvicorn.run(app, host="0.0.0.0", port=8000)
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