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AsyncSeq implementation for DynamoDB
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,91 @@ | ||
| namespace FSharp.AWS.DynamoDB | ||
|
|
||
| open Amazon.DynamoDBv2.Model | ||
| //open FSharp.AWS.DynamoDB | ||
| open FSharp.AWS.DynamoDB.ExprCommon | ||
| open FSharp.Control | ||
| open Microsoft.FSharp.Quotations | ||
| open System.Net | ||
|
|
||
| module AsyncSeq = | ||
| let private scanAsyncSeq (tableContext : TableContext<'a>) | ||
| (filterCondition : ConditionalExpr.ConditionalExpression option) | ||
| (projectionExpr : ProjectionExpr.ProjectionExpr option) (consistentRead : bool option) = | ||
| asyncSeq { | ||
| let rec aux last = | ||
| asyncSeq { | ||
| let request = new ScanRequest(tableContext.TableName) | ||
| let writer = | ||
| new AttributeWriter(request.ExpressionAttributeNames, request.ExpressionAttributeValues) | ||
| match filterCondition with | ||
| | None -> () | ||
| | Some fc -> request.FilterExpression <- fc.Write writer | ||
| match projectionExpr with | ||
| | None -> () | ||
| | Some pe -> request.ProjectionExpression <- pe.Write writer | ||
| consistentRead |> Option.iter (fun cr -> request.ConsistentRead <- cr) | ||
| last |> Option.iter (fun l -> request.ExclusiveStartKey <- l) | ||
| let! ct = Async.CancellationToken | ||
| let! response = tableContext.Client.ScanAsync(request, ct) |> Async.AwaitTaskCorrect | ||
| if response.HttpStatusCode <> HttpStatusCode.OK then | ||
| failwithf "Query request returned error %O" response.HttpStatusCode | ||
| for item in response.Items do | ||
| yield item | ||
| if response.LastEvaluatedKey.Count > 0 then yield! aux (Some response.LastEvaluatedKey) | ||
| } | ||
| yield! aux None | ||
| } | ||
|
|
||
| type TableContext<'a> with | ||
|
|
||
| /// <summary> | ||
| /// Asynchronously scans table with given condition expressions. | ||
| /// </summary> | ||
| /// <param name="filterCondition">Filter condition expression.</param> | ||
| /// <param name="limit">Maximum number of items to evaluate.</param> | ||
| /// <param name="consistentRead">Specify whether to perform consistent read operation.</param> | ||
| member __.ScanAsyncSeq(?filterCondition : ConditionExpression<'TRecord>, ?consistentRead : bool) : AsyncSeq<'a> = | ||
| let filterCondition = filterCondition |> Option.map (fun fc -> fc.Conditional) | ||
| scanAsyncSeq __ filterCondition None consistentRead | ||
| |> AsyncSeq.map __.Template.OfAttributeValues | ||
|
|
||
| /// <summary> | ||
| /// Asynchronously scans table with given condition expressions. | ||
| /// </summary> | ||
| /// <param name="filterCondition">Filter condition expression.</param> | ||
| /// <param name="limit">Maximum number of items to evaluate.</param> | ||
| /// <param name="consistentRead">Specify whether to perform consistent read operation.</param> | ||
| member __.ScanAsyncSeq(filterExpr : Expr<'a -> bool>, ?consistentRead : bool) : AsyncSeq<'a> = | ||
| let cond = __.Template.PrecomputeConditionalExpr filterExpr | ||
| __.ScanAsyncSeq(cond, ?consistentRead = consistentRead) | ||
|
|
||
| /// <summary> | ||
| /// Asynchronously scans table with given condition expressions. | ||
| /// Uses supplied projection expression to narrow downloaded attributes. | ||
| /// Projection type must be a tuple of zero or more non-conflicting properties. | ||
| /// </summary> | ||
| /// <param name="projection">Projection expression.</param> | ||
| /// <param name="filterCondition">Filter condition expression.</param> | ||
| /// <param name="limit">Maximum number of items to evaluate.</param> | ||
| /// <param name="consistentRead">Specify whether to perform consistent read operation.</param> | ||
| member __.ScanProjectedAsyncSeq(projection : ProjectionExpression<'TRecord, 'TProjection>, | ||
| ?filterCondition : ConditionExpression<'a>, ?consistentRead : bool) : AsyncSeq<'TProjection> = | ||
| let filterCondition = filterCondition |> Option.map (fun fc -> fc.Conditional) | ||
| scanAsyncSeq __ filterCondition (Some projection.ProjectionExpr) consistentRead |> AsyncSeq.map projection.UnPickle | ||
|
|
||
| /// <summary> | ||
| /// Asynchronously scans table with given condition expressions. | ||
| /// Uses supplied projection expression to narrow downloaded attributes. | ||
| /// Projection type must be a tuple of zero or more non-conflicting properties. | ||
| /// </summary> | ||
| /// <param name="projection">Projection expression.</param> | ||
| /// <param name="filterCondition">Filter condition expression.</param> | ||
| /// <param name="limit">Maximum number of items to evaluate.</param> | ||
| /// <param name="consistentRead">Specify whether to perform consistent read operation.</param> | ||
| member __.ScanProjectedAsyncSeq<'TProjection>(projection : Expr<'a -> 'TProjection>, | ||
| ?filterCondition : Expr<'a -> bool>, ?consistentRead : bool) : AsyncSeq<'TProjection> = | ||
| let filterCondition = | ||
| filterCondition |> Option.map (fun fc -> __.Template.PrecomputeConditionalExpr fc) | ||
| __.ScanProjectedAsyncSeq | ||
| (__.Template.PrecomputeProjectionExpr projection, ?filterCondition = filterCondition, | ||
| ?consistentRead = consistentRead) |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,3 +1,4 @@ | ||
| Unquote | ||
| AWSSDK.DynamoDBv2 | ||
| FSharp.Control.AsyncSeq | ||
| File: TypeShape.fs TypeShape |
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