tokio_postgres/
query.rs

1use crate::client::{InnerClient, Responses};
2use crate::codec::FrontendMessage;
3use crate::connection::RequestMessages;
4use crate::prepare::get_type;
5use crate::types::{BorrowToSql, IsNull};
6use crate::{Column, Error, Portal, Row, Statement};
7use bytes::{Bytes, BytesMut};
8use fallible_iterator::FallibleIterator;
9use futures_util::Stream;
10use log::{debug, log_enabled, Level};
11use pin_project_lite::pin_project;
12use postgres_protocol::message::backend::{CommandCompleteBody, Message};
13use postgres_protocol::message::frontend;
14use postgres_types::Type;
15use std::fmt;
16use std::pin::Pin;
17use std::sync::Arc;
18use std::task::{ready, Context, Poll};
19
20struct BorrowToSqlParamsDebug<'a, T>(&'a [T]);
21
22impl<T> fmt::Debug for BorrowToSqlParamsDebug<'_, T>
23where
24    T: BorrowToSql,
25{
26    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
27        f.debug_list()
28            .entries(self.0.iter().map(|x| x.borrow_to_sql()))
29            .finish()
30    }
31}
32
33pub async fn query<P, I>(
34    client: &InnerClient,
35    statement: Statement,
36    params: I,
37) -> Result<RowStream, Error>
38where
39    P: BorrowToSql,
40    I: IntoIterator<Item = P>,
41    I::IntoIter: ExactSizeIterator,
42{
43    let buf = if log_enabled!(Level::Debug) {
44        let params = params.into_iter().collect::<Vec<_>>();
45        debug!(
46            "executing statement {} with parameters: {:?}",
47            statement.name(),
48            BorrowToSqlParamsDebug(params.as_slice()),
49        );
50        encode(client, &statement, params)?
51    } else {
52        encode(client, &statement, params)?
53    };
54    let responses = start(client, buf).await?;
55    Ok(RowStream {
56        statement,
57        responses,
58        rows_affected: None,
59    })
60}
61
62pub async fn query_typed<P, I>(
63    client: &Arc<InnerClient>,
64    query: &str,
65    params: I,
66) -> Result<RowStream, Error>
67where
68    P: BorrowToSql,
69    I: IntoIterator<Item = (P, Type)>,
70{
71    let buf = {
72        let params = params.into_iter().collect::<Vec<_>>();
73        let param_oids = params.iter().map(|(_, t)| t.oid()).collect::<Vec<_>>();
74
75        client.with_buf(|buf| {
76            frontend::parse("", query, param_oids.into_iter(), buf).map_err(Error::parse)?;
77            encode_bind_raw("", params, "", buf)?;
78            frontend::describe(b'S', "", buf).map_err(Error::encode)?;
79            frontend::execute("", 0, buf).map_err(Error::encode)?;
80            frontend::sync(buf);
81
82            Ok(buf.split().freeze())
83        })?
84    };
85
86    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
87
88    loop {
89        match responses.next().await? {
90            Message::ParseComplete | Message::BindComplete | Message::ParameterDescription(_) => {}
91            Message::NoData => {
92                return Ok(RowStream {
93                    statement: Statement::unnamed(vec![], vec![]),
94                    responses,
95                    rows_affected: None,
96                });
97            }
98            Message::RowDescription(row_description) => {
99                let mut columns: Vec<Column> = vec![];
100                let mut it = row_description.fields();
101                while let Some(field) = it.next().map_err(Error::parse)? {
102                    let type_ = get_type(client, field.type_oid()).await?;
103                    let column = Column {
104                        name: field.name().to_string(),
105                        table_oid: Some(field.table_oid()).filter(|n| *n != 0),
106                        column_id: Some(field.column_id()).filter(|n| *n != 0),
107                        type_modifier: field.type_modifier(),
108                        r#type: type_,
109                    };
110                    columns.push(column);
111                }
112                return Ok(RowStream {
113                    statement: Statement::unnamed(vec![], columns),
114                    responses,
115                    rows_affected: None,
116                });
117            }
118            _ => return Err(Error::unexpected_message()),
119        }
120    }
121}
122
123pub async fn query_portal(
124    client: &InnerClient,
125    portal: &Portal,
126    max_rows: i32,
127) -> Result<RowStream, Error> {
128    let buf = client.with_buf(|buf| {
129        frontend::execute(portal.name(), max_rows, buf).map_err(Error::encode)?;
130        frontend::sync(buf);
131        Ok(buf.split().freeze())
132    })?;
133
134    let responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
135
136    Ok(RowStream {
137        statement: portal.statement().clone(),
138        responses,
139        rows_affected: None,
140    })
141}
142
143/// Extract the number of rows affected from [`CommandCompleteBody`].
144pub fn extract_row_affected(body: &CommandCompleteBody) -> Result<u64, Error> {
145    let rows = body
146        .tag()
147        .map_err(Error::parse)?
148        .rsplit(' ')
149        .next()
150        .unwrap()
151        .parse()
152        .unwrap_or(0);
153    Ok(rows)
154}
155
156pub async fn execute<P, I>(
157    client: &InnerClient,
158    statement: Statement,
159    params: I,
160) -> Result<u64, Error>
161where
162    P: BorrowToSql,
163    I: IntoIterator<Item = P>,
164    I::IntoIter: ExactSizeIterator,
165{
166    let buf = if log_enabled!(Level::Debug) {
167        let params = params.into_iter().collect::<Vec<_>>();
168        debug!(
169            "executing statement {} with parameters: {:?}",
170            statement.name(),
171            BorrowToSqlParamsDebug(params.as_slice()),
172        );
173        encode(client, &statement, params)?
174    } else {
175        encode(client, &statement, params)?
176    };
177    let mut responses = start(client, buf).await?;
178
179    let mut rows = 0;
180    loop {
181        match responses.next().await? {
182            Message::DataRow(_) => {}
183            Message::CommandComplete(body) => {
184                rows = extract_row_affected(&body)?;
185            }
186            Message::EmptyQueryResponse => rows = 0,
187            Message::ReadyForQuery(_) => return Ok(rows),
188            _ => return Err(Error::unexpected_message()),
189        }
190    }
191}
192
193async fn start(client: &InnerClient, buf: Bytes) -> Result<Responses, Error> {
194    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
195
196    match responses.next().await? {
197        Message::BindComplete => {}
198        _ => return Err(Error::unexpected_message()),
199    }
200
201    Ok(responses)
202}
203
204pub fn encode<P, I>(client: &InnerClient, statement: &Statement, params: I) -> Result<Bytes, Error>
205where
206    P: BorrowToSql,
207    I: IntoIterator<Item = P>,
208    I::IntoIter: ExactSizeIterator,
209{
210    client.with_buf(|buf| {
211        encode_bind(statement, params, "", buf)?;
212        frontend::execute("", 0, buf).map_err(Error::encode)?;
213        frontend::sync(buf);
214        Ok(buf.split().freeze())
215    })
216}
217
218pub fn encode_bind<P, I>(
219    statement: &Statement,
220    params: I,
221    portal: &str,
222    buf: &mut BytesMut,
223) -> Result<(), Error>
224where
225    P: BorrowToSql,
226    I: IntoIterator<Item = P>,
227    I::IntoIter: ExactSizeIterator,
228{
229    let params = params.into_iter();
230    if params.len() != statement.params().len() {
231        return Err(Error::parameters(params.len(), statement.params().len()));
232    }
233
234    encode_bind_raw(
235        statement.name(),
236        params.zip(statement.params().iter().cloned()),
237        portal,
238        buf,
239    )
240}
241
242fn encode_bind_raw<P, I>(
243    statement_name: &str,
244    params: I,
245    portal: &str,
246    buf: &mut BytesMut,
247) -> Result<(), Error>
248where
249    P: BorrowToSql,
250    I: IntoIterator<Item = (P, Type)>,
251    I::IntoIter: ExactSizeIterator,
252{
253    let (param_formats, params): (Vec<_>, Vec<_>) = params
254        .into_iter()
255        .map(|(p, ty)| (p.borrow_to_sql().encode_format(&ty) as i16, (p, ty)))
256        .unzip();
257
258    let mut error_idx = 0;
259    let r = frontend::bind(
260        portal,
261        statement_name,
262        param_formats,
263        params.into_iter().enumerate(),
264        |(idx, (param, ty)), buf| match param.borrow_to_sql().to_sql_checked(&ty, buf) {
265            Ok(IsNull::No) => Ok(postgres_protocol::IsNull::No),
266            Ok(IsNull::Yes) => Ok(postgres_protocol::IsNull::Yes),
267            Err(e) => {
268                error_idx = idx;
269                Err(e)
270            }
271        },
272        Some(1),
273        buf,
274    );
275    match r {
276        Ok(()) => Ok(()),
277        Err(frontend::BindError::Conversion(e)) => Err(Error::to_sql(e, error_idx)),
278        Err(frontend::BindError::Serialization(e)) => Err(Error::encode(e)),
279    }
280}
281
282pin_project! {
283    /// A stream of table rows.
284    #[project(!Unpin)]
285    pub struct RowStream {
286        statement: Statement,
287        responses: Responses,
288        rows_affected: Option<u64>,
289    }
290}
291
292impl Stream for RowStream {
293    type Item = Result<Row, Error>;
294
295    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
296        let this = self.project();
297        loop {
298            match ready!(this.responses.poll_next(cx)?) {
299                Message::DataRow(body) => {
300                    return Poll::Ready(Some(Ok(Row::new(this.statement.clone(), body)?)))
301                }
302                Message::CommandComplete(body) => {
303                    *this.rows_affected = Some(extract_row_affected(&body)?);
304                }
305                Message::EmptyQueryResponse | Message::PortalSuspended => {}
306                Message::ReadyForQuery(_) => return Poll::Ready(None),
307                _ => return Poll::Ready(Some(Err(Error::unexpected_message()))),
308            }
309        }
310    }
311}
312
313impl RowStream {
314    /// Returns the number of rows affected by the query.
315    ///
316    /// This function will return `None` until the stream has been exhausted.
317    pub fn rows_affected(&self) -> Option<u64> {
318        self.rows_affected
319    }
320}
321
322pub async fn sync(client: &InnerClient) -> Result<(), Error> {
323    let buf = Bytes::from_static(b"S\0\0\0\x04");
324    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
325
326    match responses.next().await? {
327        Message::ReadyForQuery(_) => Ok(()),
328        _ => Err(Error::unexpected_message()),
329    }
330}
tokio_postgres/query.rs

tokio_postgres/
query.rs
