save chart as a png

Cargo.toml

@@ -1,15 +1,21 @@
 [package]
 name = "procyon"
 version = "0.1.0"
-authors = ["François Mockers <[email protected]>"]
+authors = ["François Mockers <[email protected]>", "Thomas Aubry <[email protected]>"]
 edition = "2018"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
 [dependencies]
 vega_lite_3 = {version = "0.2", optional = true}
 vega_lite_4 = {git = "https://github.com/procyon-rs/vega_lite_4.rs.git", optional = true}
 showata = "0.2"
+tokio = {version="0.2.11", features = ["full"]}
+futures = {version="0.3.4", optional=true}
+fantoccini = {version="0.12.0"}
+base64 = {version="0.11.0"}
+serde_json = "1.0"
+retry = "1.0.0"
+futures-retry = "0.5.0"
+data-url = "0.1.0"
 
 [features]
 default = ["vega_lite_4"]

examples/save_png.rs

@@ -0,0 +1,15 @@
+use procyon::*;
+use std::path::Path;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+ let plot_save_path = Path::new("examples/output/image.png");
+ let chart = Procyon::chart(
+ "https://raw.githubusercontent.com/procyon-rs/vega_lite_4.rs/master/examples/res/data/clustered_data.csv"
+ )
+ .mark_point()
+ .encode_axis("x", "y").encode_color("cluster")
+ .save(plot_save_path).await?;
+ eprintln!("{:?}", chart);
+ Ok(())
+}

src/lib.rs

@@ -1,10 +1,10 @@
 //! High level helpers to create beautiful graphs based on Vega-Lite
 
 #![deny(
- warnings,
  missing_debug_implementations,
  trivial_casts,
  trivial_numeric_casts,
+ warnings,
  unsafe_code,
  unstable_features,
  unused_import_braces,
@@ -14,6 +14,79 @@
 
 pub use showata::Showable;
 
+use base64;
+use data_url::DataUrl;
+use fantoccini::{Client, Locator};
+use retry::{delay::Exponential, retry_with_index, OperationResult};
+//use futures_retry::{RetryPolicy, StreamRetryExt};
+use std::fs::File;
+use std::io::Write;
+use std::path::Path;
+use std::process::Command;
+
+/// Spawn in background a webdriver, currently support is limited to
+/// geckodriver. Please see [geckodriver doc](https://github.com/mozilla/geckodriver) and install it.
+/// TODO: allow [chromium webdriver](https://chromedriver.chromium.org/) and update documentation
+pub fn spawn_webdriver(
+ webdriver_name: &str,
+ port: Option<u64>,
+) -> Result<(std::process::Child, u64), Box<dyn std::error::Error>> {
+ let mut try_port = match port {
+ Some(n) => n,
+ None => 4444,
+ };
+ let webdriver_process = retry_with_index(Exponential::from_millis(100), |current_try| {
+ if current_try > 3 {
+ return OperationResult::Err("did not succeed within 3 tries");
+ }
+ try_port += current_try;
+ let try_command = Command::new(webdriver_name)
+ .args(&["--port", &try_port.to_string()])
+ .spawn();
+ match try_command {
+ Ok(cmd) => OperationResult::Ok(cmd),
+ Err(_) => OperationResult::Retry("Trying with another port"),
+ }
+ })
+ .unwrap();
+ Ok((webdriver_process, try_port))
+}
+
+/// Create a headless browser instance.
+/// Code from : https://github.com/jonhoo/fantoccini/blob/master/tests/common.rs
+/// The chrome case will be commented for now and will be tested later.str
+/// It also need the port from the webdriver.
+pub async fn create_headless_client(
+ client_type: &str,
+ port: u64,
+) -> Result<Client, fantoccini::error::NewSessionError> {
+ // let mut client = retry_with_index(Exponential::from_millis(100),
+ // |current_try| { if current_try > 5 {
+ // return OperationResult::Err("did not succeed within 3 tries");
+ // }
+ // let mut try_client = match client_type {
+ // "firefox" => {
+ // let mut caps = serde_json::map::Map::new();
+ // let opts = serde_json::json!({ "args": ["--headless"] });
+ // caps.insert("moz:firefoxOptions".to_string(), opts.clone());
+ // Client::with_capabilities(&format!("http://localhost:{}", port.to_string()), caps)
+ // .await?
+ // }
+ // browser => unimplemented!("unsupported browser backend {}",
+ // browser), };
+ // match try_client {
+ // Ok(try_client) => OperationResult::Ok(try_client),
+ // Err(e) => OperationResult::Retry("Trying to establish connection
+ // between client and webdriver"), }
+ // }).unwrap();
+ // Ok(client)
+ unimplemented!(
+ "Currently trying to find out how retry_futures works {} {}",
+ client_type,
+ port
+ )
+}
+
 #[cfg(feature = "vega_lite_4")]
 mod vega_lite_4_bindings;
 
@@ -116,6 +189,47 @@ impl Procyon {
  new
  }
 
+ /// Current implem use the saved html by showata and imitate user clik to
+ /// save the image Another approach is to updated the embeded js like in
+ /// altair: https://github.com/altair-viz/altair_saver/blob/master/altair_saver/savers/_selenium.py
+ pub async fn save(&self, image_path: &Path) -> Result<(), Box<dyn std::error::Error>> {
+ let (mut webdriver_process, webdriver_port) =
+ spawn_webdriver("geckodriver", Some(4444)).unwrap();
+ let mut client = create_headless_client("firefox", webdriver_port).await?;
+ client
+ .goto(&format!(
+ "file:///private{}",
+ self.build().to_html_file()?.to_str().unwrap()
+ ))
+ .await?;
+
+ let mut summary_button = client
+ .wait_for_find(Locator::Css("summary"))
+ .await?
+ .click()
+ .await?;
+ let mut hidden_link = summary_button
+ .find(Locator::LinkText("Save as PNG"))
+ .await?
+ .click()
+ .await?;
+
+ let link = hidden_link
+ .find(Locator::LinkText("Save as PNG"))
+ .await?
+ .attr("href")
+ .await?
+ .unwrap();
+
+ let image_data_url = DataUrl::process(&link).unwrap();
+ let (body, _) = image_data_url.decode_to_vec().unwrap();
+ let bytes: Vec<u8> = base64::decode(&body).unwrap();
+ let mut image_file = File::create(image_path).unwrap();
+ image_file.write(&bytes).unwrap();
+ hidden_link.close().await?;
+ webdriver_process.kill()?;
+ Ok(())
+ }
  /// Build the graph
  #[cfg(feature = "vega_lite_4")]
  pub fn build(&self) -> vega_lite_4::Vegalite {