1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

use async_stream::try_stream;
use futures_core::stream::Stream;
use futures_util::{pin_mut, StreamExt};
use reqwest::Url;
use std::time::Duration;
use tokio::time::delay_for;

use crate::error::Error;

pub struct Builder {
    url: Url,
    size: u64,
    offset: u64,
    retry_delay: Option<Duration>,
    receive_timeout: Option<Duration>,
    retry_count: u32,
    client: reqwest::Client,
}

impl Builder {
    pub fn new(url: Url, offset: u64, size: u64) -> Self {
        Self {
            url,
            offset,
            size,
            retry_delay: None,
            retry_count: 0,
            receive_timeout: None,
            client: reqwest::Client::new(),
        }
    }
    pub fn retry(mut self, retry_count: u32, retry_delay: Option<Duration>) -> Self {
        self.retry_delay = retry_delay;
        self.retry_count = retry_count;
        self
    }
    pub fn receive_timeout(mut self, timeout: Option<Duration>) -> Self {
        self.receive_timeout = timeout;
        self
    }
    fn stream_fail(
        client: reqwest::Client,
        offset: u64,
        size: u64,
        url: Url,
        timeout: Option<Duration>,
    ) -> impl Stream<Item = Result<bytes::Bytes, Error>> {
        try_stream! {
            log::info!("Requesting {}, starting at offset {} with size {}...", url, offset, size);
            let end_offset = offset + size - 1;
            let mut request = client.get(url).header(
                reqwest::header::RANGE,
                format!("bytes={}-{}", offset, end_offset),
            );
            if let Some(timeout) = timeout {
                request = request.timeout(timeout);
            }
            let response = request.send().await.map_err(|err| ("request failed", err))?;
            let mut stream = response.bytes_stream();
            while let Some(item) = stream.next().await {
                let chunk = item.map_err(|err| ("receive failed", err))?;
                yield chunk;
            }
        }
    }
    pub fn stream(mut self) -> impl Stream<Item = Result<bytes::Bytes, Error>> {
        try_stream! {
            loop {
                let stream = Self::stream_fail(
                    self.client.clone(),
                    self.offset,
                    self.size,
                    self.url.clone(),
                    self.receive_timeout.clone(),
                );
                pin_mut!(stream);
                while let Some(result) = stream.next().await {
                    match result {
                        Ok(item) => {
                            self.offset += item.len() as u64;
                            self.size -= item.len() as u64;
                            yield item
                        },
                        Err(err) => if self.retry_count == 0 {
                            Err(err)?
                        } else {
                            log::warn!("request for {} failed (retrying soon): {}", self.url, err);
                            self.retry_count -= 1;
                        }
                    };
                }
                if let Some(retry_delay) = self.retry_delay {
                    delay_for(retry_delay).await;
                }
            }
        }
    }
    pub async fn single_fail(
        client: reqwest::Client,
        offset: u64,
        size: u64,
        url: Url,
        timeout: Option<Duration>,
    ) -> Result<bytes::Bytes, Error> {
        let end_offset = offset + size - 1;
        let mut request = client.get(url).header(
            reqwest::header::RANGE,
            format!("bytes={}-{}", offset, end_offset),
        );
        if let Some(timeout) = timeout {
            request = request.timeout(timeout);
        }
        let response = request
            .send()
            .await
            .map_err(|err| ("request failed", err))?;
        response
            .bytes()
            .await
            .map_err(|err| ("receive failed", err).into())
    }
    pub async fn single(mut self) -> Result<bytes::Bytes, Error> {
        loop {
            match Self::single_fail(
                self.client.clone(),
                self.offset,
                self.size,
                self.url.clone(),
                self.receive_timeout,
            )
            .await
            {
                Ok(item) => return Ok(item),
                Err(err) => {
                    if self.retry_count == 0 {
                        return Err(err);
                    } else {
                        log::warn!("request for {} failed (retrying soon): {}", self.url, err);
                        self.retry_count -= 1;
                    }
                }
            }
            if let Some(retry_delay) = self.retry_delay {
                delay_for(retry_delay).await;
            }
        }
    }
}