Skip to content

Instantly share code, notes, and snippets.

@HirotoShioi
Created October 9, 2019 06:12
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
Star You must be signed in to star a gist
Save HirotoShioi/5813fd1c0b78e42361091cccc711db73 to your computer and use it in GitHub Desktop.
An example of using Google Cloud Vision API using serde_json and reqwest
extern crate hex; // 0.4.0
extern crate reqwest; // 0.9.20
extern crate serde_json; // 1.0
use reqwest::{StatusCode, Url};
use serde_json::{json, Value};
use std::fmt;
use std::fs;
pub fn get_dominant_colors(image_url: &Url) -> Result<Vec<Color>, Box<dyn std::error::Error>> {
let response_json = use_cloud_vision_api(image_url)?;
let extracted = extract_colors(&response_json)?;
Ok(extracted)
}
const CLOUD_VISION_URI: &str = "https://vision.googleapis.com/v1/images:annotate";
const API_KEY_FILE_PATH: &str = "./secrets/vision_api";
fn use_cloud_vision_api(image_url: &Url) -> Result<Value, Box<dyn std::error::Error>> {
let request = json!({
"requests": [
{
"image": {
"source": {
"imageUri": image_url.to_owned().into_string()
}
},
"features": [
{
"maxResults": 10,
"type": "IMAGE_PROPERTIES"
}
]
}
]
});
let secret_key = fs::read_to_string(API_KEY_FILE_PATH)?;
let mut response = reqwest::Client::new()
.post(CLOUD_VISION_URI)
.query(&[("key", secret_key)])
.json(&request)
.send()?;
if response.status() != StatusCode::OK {
return Err(Box::new(CloudVisionError::BadRequest));
}
let response_json: Value = response.json()?;
let err = &response_json["responses"][0]["error"];
if err.is_object() {
return Err(Box::new(CloudVisionError::FailedToParseImage));
}
Ok(response_json)
}
fn extract_colors(val: &Value) -> Result<Vec<Color>, CloudVisionError> {
let colors = &val["responses"][0]["imagePropertiesAnnotation"]["dominantColors"]["colors"];
match colors.as_array() {
Some(color_ary) => {
let mut color_vec = Vec::new();
for color_value in color_ary.iter() {
if let Some(color) = to_color(color_value) {
color_vec.push(color);
} else {
return Err(CloudVisionError::UnableToParseColorData);
};
}
Ok(color_vec)
}
None => Err(CloudVisionError::UnableToParseColorData),
}
}
#[derive(Debug)]
pub struct Color {
pub pixel_fraction: f32,
pub score: f32,
pub hex_color: String,
}
#[derive(Debug)]
enum CloudVisionError {
BadRequest,
UnableToParseColorData,
FailedToParseImage,
}
impl std::error::Error for CloudVisionError {}
impl fmt::Display for CloudVisionError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> fmt::Result {
let error_message = match self {
CloudVisionError::BadRequest => "Bad request",
CloudVisionError::FailedToParseImage => "Cloud vision api failed to parse image",
CloudVisionError::UnableToParseColorData => "Unable to parse data",
};
write!(f, "{}", error_message)
}
}
//Construct `Color` struct with given `Value`
fn to_color(value: &Value) -> Option<Color> {
let pixel_fraction = value.get("pixelFraction")?.as_f64()? as f32;
let score = value.get("score")?.as_f64()? as f32;
let color = &value.get("color")?;
let red: u8 = color.get("red")?.to_owned().as_u64()? as u8;
let green: u8 = color.get("green")?.to_owned().as_u64()? as u8;
let blue: u8 = color.get("blue")?.to_owned().as_u64()? as u8;
//Construct hex string color
let mut hex_color = String::from("#");
let hex = hex::encode(vec![red, green, blue]);
hex_color.push_str(&hex);
let color_struct = Color {
pixel_fraction,
score,
hex_color,
};
Some(color_struct)
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment