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                        r#type: type_,
108                    };
109                    columns.push(column);
110                }
111                return Ok(RowStream {
112                    statement: Statement::unnamed(vec![], columns),
113                    responses,
114                    rows_affected: None,
115                });
116            }
117            _ => return Err(Error::unexpected_message()),
118        }
119    }
120}
121
122pub async fn query_portal(
123    client: &InnerClient,
124    portal: &Portal,
125    max_rows: i32,
126) -> Result<RowStream, Error> {
127    let buf = client.with_buf(|buf| {
128        frontend::execute(portal.name(), max_rows, buf).map_err(Error::encode)?;
129        frontend::sync(buf);
130        Ok(buf.split().freeze())
131    })?;
132
133    let responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
134
135    Ok(RowStream {
136        statement: portal.statement().clone(),
137        responses,
138        rows_affected: None,
139    })
140}
141
142/// Extract the number of rows affected from [`CommandCompleteBody`].
143pub fn extract_row_affected(body: &CommandCompleteBody) -> Result<u64, Error> {
144    let rows = body
145        .tag()
146        .map_err(Error::parse)?
147        .rsplit(' ')
148        .next()
149        .unwrap()
150        .parse()
151        .unwrap_or(0);
152    Ok(rows)
153}
154
155pub async fn execute<P, I>(
156    client: &InnerClient,
157    statement: Statement,
158    params: I,
159) -> Result<u64, Error>
160where
161    P: BorrowToSql,
162    I: IntoIterator<Item = P>,
163    I::IntoIter: ExactSizeIterator,
164{
165    let buf = if log_enabled!(Level::Debug) {
166        let params = params.into_iter().collect::<Vec<_>>();
167        debug!(
168            "executing statement {} with parameters: {:?}",
169            statement.name(),
170            BorrowToSqlParamsDebug(params.as_slice()),
171        );
172        encode(client, &statement, params)?
173    } else {
174        encode(client, &statement, params)?
175    };
176    let mut responses = start(client, buf).await?;
177
178    let mut rows = 0;
179    loop {
180        match responses.next().await? {
181            Message::DataRow(_) => {}
182            Message::CommandComplete(body) => {
183                rows = extract_row_affected(&body)?;
184            }
185            Message::EmptyQueryResponse => rows = 0,
186            Message::ReadyForQuery(_) => return Ok(rows),
187            _ => return Err(Error::unexpected_message()),
188        }
189    }
190}
191
192async fn start(client: &InnerClient, buf: Bytes) -> Result<Responses, Error> {
193    let mut responses = client.send(RequestMessages::Single(FrontendMessage::Raw(buf)))?;
194
195    match responses.next().await? {
196        Message::BindComplete => {}
197        _ => return Err(Error::unexpected_message()),
198    }
199
200    Ok(responses)
201}
202
203pub fn encode<P, I>(client: &InnerClient, statement: &Statement, params: I) -> Result<Bytes, Error>
204where
205    P: BorrowToSql,
206    I: IntoIterator<Item = P>,
207    I::IntoIter: ExactSizeIterator,
208{
209    client.with_buf(|buf| {
210        encode_bind(statement, params, "", buf)?;
211        frontend::execute("", 0, buf).map_err(Error::encode)?;
212        frontend::sync(buf);
213        Ok(buf.split().freeze())
214    })
215}
216
217pub fn encode_bind<P, I>(
218    statement: &Statement,
219    params: I,
220    portal: &str,
221    buf: &mut BytesMut,
222) -> Result<(), Error>
223where
224    P: BorrowToSql,
225    I: IntoIterator<Item = P>,
226    I::IntoIter: ExactSizeIterator,
227{
228    let params = params.into_iter();
229    if params.len() != statement.params().len() {
230        return Err(Error::parameters(params.len(), statement.params().len()));
231    }
232
233    encode_bind_raw(
234        statement.name(),
235        params.zip(statement.params().iter().cloned()),
236        portal,
237        buf,
238    )
239}
240
241fn encode_bind_raw<P, I>(
242    statement_name: &str,
243    params: I,
244    portal: &str,
245    buf: &mut BytesMut,
246) -> Result<(), Error>
247where
248    P: BorrowToSql,
249    I: IntoIterator<Item = (P, Type)>,
250    I::IntoIter: ExactSizeIterator,
251{
252    let (param_formats, params): (Vec<_>, Vec<_>) = params
253        .into_iter()
254        .map(|(p, ty)| (p.borrow_to_sql().encode_format(&ty) as i16, (p, ty)))
255        .unzip();
256
257    let mut error_idx = 0;
258    let r = frontend::bind(
259        portal,
260        statement_name,
261        param_formats,
262        params.into_iter().enumerate(),
263        |(idx, (param, ty)), buf| match param.borrow_to_sql().to_sql_checked(&ty, buf) {
264            Ok(IsNull::No) => Ok(postgres_protocol::IsNull::No),
265            Ok(IsNull::Yes) => Ok(postgres_protocol::IsNull::Yes),
266            Err(e) => {
267                error_idx = idx;
268                Err(e)
269            }
270        },
271        Some(1),
272        buf,
273    );
274    match r {
275        Ok(()) => Ok(()),
276        Err(frontend::BindError::Conversion(e)) => Err(Error::to_sql(e, error_idx)),
277        Err(frontend::BindError::Serialization(e)) => Err(Error::encode(e)),
278    }
279}
280
281pin_project! {
282    /// A stream of table rows.
283    #[project(!Unpin)]
284    pub struct RowStream {
285        statement: Statement,
286        responses: Responses,
287        rows_affected: Option<u64>,
288    }
289}
290
291impl Stream for RowStream {
292    type Item = Result<Row, Error>;
293
294    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
295        let this = self.project();
296        loop {
297            match ready!(this.responses.poll_next(cx)?) {
298                Message::DataRow(body) => {
299                    return Poll::Ready(Some(Ok(Row::new(this.statement.clone(), body)?)))
300                }
301                Message::CommandComplete(body) => {
302                    *this.rows_affected = Some(extract_row_affected(&body)?);
303                }
304                Message::EmptyQueryResponse | Message::PortalSuspended => {}
305                Message::ReadyForQuery(_) => return Poll::Ready(None),
306                _ => return Poll::Ready(Some(Err(Error::unexpected_message()))),
307            }
308        }
309    }
310}
311
312impl RowStream {
313    /// Returns the number of rows affected by the query.
314    ///
315    /// This function will return `None` until the stream has been exhausted.
316    pub fn rows_affected(&self) -> Option<u64> {
317        self.rows_affected
318    }
319}
tokio_postgres/query.rs

tokio_postgres/
query.rs
