Closes #77 by removing the experimental middleware code
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Sean Corfield
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2 changed files with 0 additions and 191 deletions
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;; copyright (c) 2019-2020 Sean Corfield, all rights reserved
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(ns next.jdbc.middleware
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"This is just an experimental sketch of what it might look like to be
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able to provide middleware that can wrap SQL execution in a way that
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behavior can be extended in interesting ways, to support logging, timing.
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and other cross-cutting things.
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Since it's just an experiment, there's no guarantee that this -- or
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anything like it -- will actually end up in a next.jdbc release. You've
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been warned!
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So far these execution points can be hooked into:
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* start -- pre-process the SQL & parameters and options
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* (execute SQL)
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* ????? -- process the options (and something else?)
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* row -- post-process each row and options
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* rs -- post-process the whole result set and options
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For the rows and result set, it's 'obvious' that the functions should
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take the values and return them (or updated versions). For the start
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function with SQL & parameters, it also makes sense to take and return
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that vector.
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For timing middleware, you'd need to pass data through the call chain
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somehow -- unless you control the whole middleware and this isn't sufficient
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for that yet. Hence the decision to allow processing of the options and
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passing data through those -- which leads to a rather odd call chain:
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start can return the vector or a map of updated options (with a payload),
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and the ????? point can process the options again (e.g., to update timing
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data etc). And that's all kind of horrible."
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(:require [next.jdbc.protocols :as p]
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[next.jdbc.result-set :as rs]))
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(defn post-processing-adapter
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"Given a builder function (e.g., `as-lower-maps`), return a new builder
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function that post-processes rows and the result set. The options may
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contain post-processing functions that are called on each row and on the
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the result set. The options map is provided as a second parameter to these
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functions, which should include `:next.jdbc/sql-params` (the vector of SQL
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and parameters, in case post-processing needs it):
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* `:execute-fn` -- called immediately after the SQL operation completes
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^ This is a horrible name and it needs to return the options which
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is weird so I don't like this approach overall...
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* `:row!-fn` -- called on each row as it is fully-realized
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* `:rs!-fn` -- called on the whole result set once it is fully-realized
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The results of these functions are returned as the rows/result set."
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[builder-fn]
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(fn [rs opts]
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(let [id2 (fn [x _] x)
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id2' (fn [_ x] x)
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exec-fn (get opts :execute-fn id2')
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opts (exec-fn rs opts)
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mrsb (builder-fn rs opts)
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row!-fn (get opts :row!-fn id2)
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rs!-fn (get opts :rs!-fn id2)]
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(reify
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rs/RowBuilder
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(->row [this] (rs/->row mrsb))
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(column-count [this] (rs/column-count mrsb))
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(with-column [this row i] (rs/with-column mrsb row i))
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(row! [this row] (row!-fn (rs/row! mrsb row) opts))
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rs/ResultSetBuilder
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(->rs [this] (rs/->rs mrsb))
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(with-row [this mrs row] (rs/with-row mrsb mrs row))
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(rs! [this mrs] (rs!-fn (rs/rs! mrsb mrs) opts))))))
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(defrecord JdbcMiddleware [db global-opts]
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p/Executable
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(-execute [this sql-params opts]
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(let [opts (merge global-opts opts)
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id2 (fn [x _] x)
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builder-fn (get opts :builder-fn rs/as-maps)
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sql-params-fn (get opts :sql-params-fn id2)
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result (sql-params-fn sql-params opts)
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sql-params' (if (map? result)
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(or (:next.jdbc/sql-params result) sql-params)
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result)]
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(p/-execute db sql-params'
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(assoc (if (map? result) result opts)
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:builder-fn (post-processing-adapter builder-fn)
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:next.jdbc/sql-params sql-params'))))
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(-execute-one [this sql-params opts]
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(let [opts (merge global-opts opts)
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id2 (fn [x _] x)
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builder-fn (get opts :builder-fn rs/as-maps)
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sql-params-fn (get opts :sql-params-fn id2)
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result (sql-params-fn sql-params opts)
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sql-params' (if (map? result)
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(or (:next.jdbc/sql-params result) sql-params)
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result)]
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(p/-execute-one db sql-params'
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(assoc (if (map? result) result opts)
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:builder-fn (post-processing-adapter builder-fn)
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:next.jdbc/sql-params sql-params'))))
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(-execute-all [this sql-params opts]
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(let [opts (merge global-opts opts)
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id2 (fn [x _] x)
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builder-fn (get opts :builder-fn rs/as-maps)
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sql-params-fn (get opts :sql-params-fn id2)
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result (sql-params-fn sql-params opts)
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sql-params' (if (map? result)
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(or (:next.jdbc/sql-params result) sql-params)
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result)]
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(p/-execute-all db sql-params'
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(assoc (if (map? result) result opts)
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:builder-fn (post-processing-adapter builder-fn)
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:next.jdbc/sql-params sql-params')))))
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(defn wrapper
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""
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([db] (JdbcMiddleware. db {}))
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([db opts] (JdbcMiddleware. db opts)))
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@ -1,76 +0,0 @@
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;; copyright (c) 2019-2020 Sean Corfield, all rights reserved
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(ns next.jdbc.middleware-test
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(:require [clojure.test :refer [deftest is use-fixtures]]
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[next.jdbc :as jdbc]
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[next.jdbc.middleware :as mw]
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[next.jdbc.test-fixtures :refer [with-test-db db ds
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default-options]]
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[next.jdbc.result-set :as rs]
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[next.jdbc.specs :as specs]))
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(set! *warn-on-reflection* true)
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(use-fixtures :once with-test-db)
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(specs/instrument)
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(deftest logging-test
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(let [logging (atom [])
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logger (fn [data _] (swap! logging conj data) data)
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sql-p ["select * from fruit where id in (?,?) order by id desc" 1 4]]
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(jdbc/execute! (mw/wrapper (ds))
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sql-p
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(assoc (default-options)
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:builder-fn rs/as-lower-maps
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:sql-params-fn logger
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:row!-fn logger
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:rs!-fn logger))
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;; should log four things
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(is (= 4 (-> @logging count)))
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;; :next.jdbc/sql-params value
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(is (= sql-p (-> @logging (nth 0))))
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;; first row (with PK 4)
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(is (= 4 (-> @logging (nth 1) :fruit/id)))
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;; second row (with PK 1)
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(is (= 1 (-> @logging (nth 2) :fruit/id)))
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;; full result set with two rows
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(is (= 2 (-> @logging (nth 3) count)))
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(is (= [4 1] (-> @logging (nth 3) (->> (map :fruit/id)))))
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;; now repeat without the row logging
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(reset! logging [])
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(jdbc/execute! (mw/wrapper (ds)
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{:builder-fn rs/as-lower-maps
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:sql-params-fn logger
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:rs!-fn logger})
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sql-p
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(default-options))
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;; should log two things
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(is (= 2 (-> @logging count)))
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;; :next.jdbc/sql-params value
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(is (= sql-p (-> @logging (nth 0))))
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;; full result set with two rows
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(is (= 2 (-> @logging (nth 1) count)))
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(is (= [4 1] (-> @logging (nth 1) (->> (map :fruit/id)))))))
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(deftest timing-test
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(let [timing (atom {:calls 0 :total 0.0})
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start-fn (fn [_ opts]
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(swap! (:timing opts) update :calls inc)
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(assoc opts :start (System/nanoTime)))
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exec-fn (fn [_ opts]
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(let [end (System/nanoTime)]
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(swap! (:timing opts) update :total + (- end (:start opts)))
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opts))
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sql-p ["select * from fruit where id in (?,?) order by id desc" 1 4]]
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(jdbc/execute! (mw/wrapper (ds) {:timing timing
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:sql-params-fn start-fn
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:execute-fn exec-fn})
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sql-p)
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(jdbc/execute! (mw/wrapper (ds) {:timing timing
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:sql-params-fn start-fn
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:execute-fn exec-fn})
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sql-p)
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(println (format "%6s %d calls took %,10d nanoseconds"
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(:dbtype (db)) (:calls @timing) (long (:total @timing))))))
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