Command line script to generate an image from Replicate using the Nano Banana Pro model

generate_image.sh

#!/bin/bash

# Generate an image from a text prompt using Replicate API
# Usage: ./generate_image.sh "paris in the spring"

# Make sure to put the REPLICATE_API_TOKEN in your .env or environment

set -e

# Load .env file if it exists (check script dir, then current dir)
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
if [ -f "$SCRIPT_DIR/../.env" ]; then
  set -a; source "$SCRIPT_DIR/../.env"; set +a
elif [ -f ".env" ]; then
  set -a; source ".env"; set +a
fi

if [ -z "$1" ]; then
  echo "Usage: $0 \"your prompt here\"" >&2
  exit 1
fi

if [ -z "$REPLICATE_API_TOKEN" ]; then
  echo "Error: REPLICATE_API_TOKEN environment variable is not set" >&2
  exit 1
fi

PROMPT="$1"
OUTPUT_DIR="${2:-/tmp}"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
SAFE_PROMPT=$(echo "$PROMPT" | tr ' ' '_' | tr -cd '[:alnum:]_' | cut -c1-50)
OUTPUT_FILE="${OUTPUT_DIR}/image_${SAFE_PROMPT}_${TIMESTAMP}.png"

echo "Generating image for: \"$PROMPT\"" >&2

# Call Replicate API
RESPONSE=$(curl -s -X POST \
  -H "Authorization: Bearer $REPLICATE_API_TOKEN" \
  -H "Content-Type: application/json" \
  -H "Prefer: wait" \
  -d "{
    \"input\": {
      \"prompt\": \"$PROMPT\",
      \"resolution\": \"1K\",
      \"image_input\": [],
      \"aspect_ratio\": \"21:9\",
      \"output_format\": \"png\",
      \"safety_filter_level\": \"block_only_high\"
    }
  }" \
  https://api.replicate.com/v1/models/google/nano-banana-pro/predictions)

# Check for actual errors (not "error":null)
if echo "$RESPONSE" | grep -qE '"error":\s*"[^"]'; then
  ERROR=$(echo "$RESPONSE" | grep -o '"error":"[^"]*"' | head -1)
  echo "API Error: $ERROR" >&2
  exit 1
fi

# Poll for completion if not yet succeeded
while ! echo "$RESPONSE" | grep -q '"status":"succeeded"'; do
  STATUS=$(echo "$RESPONSE" | grep -o '"status":"[^"]*"' | sed 's/"status":"//' | sed 's/"$//')

  if [ "$STATUS" = "failed" ] || [ "$STATUS" = "canceled" ]; then
    echo "Error: Prediction $STATUS" >&2
    exit 1
  fi

  # Get the polling URL
  GET_URL=$(echo "$RESPONSE" | grep -o '"get":"[^"]*"' | sed 's/"get":"//' | sed 's/"$//')

  if [ -z "$GET_URL" ]; then
    echo "Error: Could not find polling URL" >&2
    exit 1
  fi

  echo "Status: $STATUS, waiting..." >&2
  sleep 2

  RESPONSE=$(curl -s -H "Authorization: Bearer $REPLICATE_API_TOKEN" "$GET_URL")
done

# Extract image URL from response
IMAGE_URL=$(echo "$RESPONSE" | grep -o '"output":"https://[^"]*"' | sed 's/"output":"//' | sed 's/"$//')

if [ -z "$IMAGE_URL" ]; then
  # Try array format output
  IMAGE_URL=$(echo "$RESPONSE" | grep -o '"output":\s*\["[^"]*"\]' | grep -o 'https://[^"]*')
fi

if [ -z "$IMAGE_URL" ]; then
  echo "Error: Could not extract image URL from response" >&2
  echo "Response: $RESPONSE" >&2
  exit 1
fi

# Download the image
echo "Downloading image..." >&2
curl -s -o "$OUTPUT_FILE" "$IMAGE_URL"

if [ -f "$OUTPUT_FILE" ] && [ -s "$OUTPUT_FILE" ]; then
  echo "$OUTPUT_FILE"
else
  echo "Error: Failed to download image" >&2
  exit 1
fi