[WIP] Single download by uid endpoint

modules/renter.go

@@ -84,6 +84,7 @@ type DownloadInfo struct {
 	StartTime            time.Time `json:"starttime"`            // The time when the download was started.
 	StartTimeUnix        int64     `json:"starttimeunix"`        // The time when the download was started in unix format.
 	TotalDataTransferred uint64    `json:"totaldatatransferred"` // Total amount of data transferred, including negotiation, etc.
+	UID                  string    `json:"uid"`                  // unique identifier that can be used to retrieve a specific download info.
 }
 
 // FileUploadParams contains the information used by the Renter to upload a
@@ -335,6 +336,11 @@ type Renter interface {
 	// began.
 	CurrentPeriod() types.BlockHeight
 
+	// DownloadByUID retrieves the download with the specified uid. It returns a
+	// DownloadInfo object and true if the object was found. Otherwise it returns
+	// false.
+	DownloadByUID(uid string) (DownloadInfo, bool)
+
 	// PeriodSpending returns the amount spent on contracts in the current
 	// billing period.
 	PeriodSpending() ContractorSpending

modules/renter/download.go

@@ -124,6 +124,7 @@ package renter
 // heap.
 
 import (
+	"encoding/hex"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -134,6 +135,7 @@ import (
 	"github.com/NebulousLabs/Sia/modules"
 	"github.com/NebulousLabs/Sia/persist"
 	"github.com/NebulousLabs/Sia/types"
+	"github.com/NebulousLabs/fastrand"
 
 	"github.com/NebulousLabs/errors"
 )
@@ -168,6 +170,7 @@ type (
 		staticPriority      uint64        // Downloads with higher priority will complete first.
 
 		// Utilities.
+		uid           string
 		log           *persist.Logger // Same log as the renter.
 		memoryManager *memoryManager  // Same memoryManager used across the renter.
 		mu            sync.Mutex      // Unique to the download object.
@@ -374,6 +377,8 @@ func (r *Renter) managedNewDownload(params downloadParams) (*download, error) {
 
 		log:           r.log,
 		memoryManager: r.memoryManager,
+
+		uid: hex.EncodeToString(fastrand.Bytes(8)),
 	}
 
 	// Determine which chunks to download.
@@ -476,14 +481,56 @@ func (r *Renter) managedNewDownload(params downloadParams) (*download, error) {
 	return d, nil
 }
 
+// DownloadByUID retrieves the download with the specified uid. It returns a
+// DownloadInfo object and true if the object was found. Otherwise it returns
+// false.
+func (r *Renter) DownloadByUID(uid string) (modules.DownloadInfo, bool) {
+	r.downloadHistoryMu.Lock()
+	defer r.downloadHistoryMu.Unlock()
+
+	for i := range r.downloadHistory {
+		if r.downloadHistory[i].uid != uid {
+			continue
+		}
+		// Order from most recent to least recent.
+		d := r.downloadHistory[i]
+		d.mu.Lock() // Lock required for d.endTime only.
+		download := modules.DownloadInfo{
+			Destination:     d.destinationString,
+			DestinationType: d.staticDestinationType,
+			Length:          d.staticLength,
+			Offset:          d.staticOffset,
+			SiaPath:         d.staticSiaPath,
+
+			Completed:            d.staticComplete(),
+			EndTime:              d.endTime,
+			Received:             atomic.LoadUint64(&d.atomicDataReceived),
+			StartTime:            d.staticStartTime,
+			StartTimeUnix:        d.staticStartTime.UnixNano(),
+			TotalDataTransferred: atomic.LoadUint64(&d.atomicTotalDataTransferred),
+			UID:                  d.uid,
+		}
+		// Release download lock before calling d.Err(), which will acquire the
+		// lock. The error needs to be checked separately because we need to
+		// know if it's 'nil' before grabbing the error string.
+		d.mu.Unlock()
+		if d.Err() != nil {
+			download.Error = d.Err().Error()
+		} else {
+			download.Error = ""
+		}
+		return download, true
+	}
+	return modules.DownloadInfo{}, false
+}
+
 // DownloadHistory returns the list of downloads that have been performed. Will
 // include downloads that have not yet completed. Downloads will be roughly,
 // but not precisely, sorted according to start time.
 //
 // TODO: Currently the DownloadHistory only contains downloads from this
-// session, does not contain downloads that were executed for the purposes of
-// repairing, and has no way to clear the download history if it gets long or
-// unwieldy. It's not entirely certain which of the missing features are
+// session and does not contain downloads that were executed for the purposes of
+// repairing. It's not entirely certain which of the missing features are
 // actually desirable, please consult core team + app dev community before
 // deciding what to implement.
 func (r *Renter) DownloadHistory() []modules.DownloadInfo {
@@ -508,6 +555,7 @@ func (r *Renter) DownloadHistory() []modules.DownloadInfo {
 			StartTime:            d.staticStartTime,
 			StartTimeUnix:        d.staticStartTime.UnixNano(),
 			TotalDataTransferred: atomic.LoadUint64(&d.atomicTotalDataTransferred),
+			UID:                  d.uid,
 		}
 		// Release download lock before calling d.Err(), which will acquire the
 		// lock. The error needs to be checked separately because we need to

node/api/client/renter.go

@@ -96,6 +96,13 @@ func (c *Client) RenterClearDownloadsRangePost(after, before time.Time) (err err
 	return
 }
 
+// RenterDownloadByUID requests the /renter/downloads endpoint to get the
+// history of a single download with the specified UID.
+func (c *Client) RenterDownloadByUID(uid string) (di api.DownloadInfo, err error) {
+	err = c.get(fmt.Sprintf("/renter/downloads?uid=%s", uid), &di)
+	return
+}
+
 // RenterDownloadsGet requests the /renter/downloads resource
 func (c *Client) RenterDownloadsGet() (rdq api.RenterDownloadQueue, err error) {
 	err = c.get("/renter/downloads", &rdq)

node/api/renter.go

@@ -168,6 +168,7 @@ type (
 		StartTime            time.Time `json:"starttime"`            // The time when the download was started.
 		StartTimeUnix        int64     `json:"starttimeunix"`        // The time when the download was started in unix format.
 		TotalDataTransferred uint64    `json:"totaldatatransferred"` // The total amount of data transferred, including negotiation, overdrive etc.
+		UID                  string    `json:"uid"`                  // unique identifier that can be used to retrieve a specific download info.
 	}
 )
 
@@ -439,7 +440,36 @@ func (api *API) renterClearDownloadsHandler(w http.ResponseWriter, req *http.Req
 }
 
 // renterDownloadsHandler handles the API call to request the download queue.
-func (api *API) renterDownloadsHandler(w http.ResponseWriter, _ *http.Request, _ httprouter.Params) {
+func (api *API) renterDownloadsHandler(w http.ResponseWriter, req *http.Request, _ httprouter.Params) {
+	// If a specific uid was specified we return a single download.
+	uid := req.FormValue("uid")
+	if uid != "" {
+		di, ok := api.renter.DownloadByUID(uid)
+		if !ok {
+			WriteError(w, Error{"Couldn't find download for specified UID"}, http.StatusBadRequest)
+			return
+		}
+		WriteJSON(w, DownloadInfo{
+			Destination:     di.Destination,
+			DestinationType: di.DestinationType,
+			Filesize:        di.Length,
+			Length:          di.Length,
+			Offset:          di.Offset,
+			SiaPath:         di.SiaPath,
+
+			Completed:            di.Completed,
+			EndTime:              di.EndTime,
+			Error:                di.Error,
+			Received:             di.Received,
+			StartTime:            di.StartTime,
+			StartTimeUnix:        di.StartTimeUnix,
+			TotalDataTransferred: di.TotalDataTransferred,
+			UID:                  di.UID,
+		})
+		return
+	}
+
+	// Otherwise we return the whole history.
 	var downloads []DownloadInfo
 	for _, di := range api.renter.DownloadHistory() {
 		downloads = append(downloads, DownloadInfo{
@@ -457,6 +487,7 @@ func (api *API) renterDownloadsHandler(w http.ResponseWriter, _ *http.Request, _
 			StartTime:            di.StartTime,
 			StartTimeUnix:        di.StartTimeUnix,
 			TotalDataTransferred: di.TotalDataTransferred,
+			UID:                  di.UID,
 		})
 	}
 	WriteJSON(w, RenterDownloadQueue{

siatest/renter/renter_test.go

@@ -125,6 +125,17 @@ func testClearDownloadHistory(t *testing.T, tg *siatest.TestGroup) {
 	}
 	numDownloads = len(rdg.Downloads)
 
+	// Make sure that we can also individually grab all the downloads.
+	for _, di := range rdg.Downloads {
+		d, err := r.RenterDownloadByUID(di.UID)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !reflect.DeepEqual(d, di) {
+			t.Fatal("download infos are not equal")
+		}
+	}
+
 	// Check removing one download from history
 	// Remove First Download
 	timestamp := rdg.Downloads[0].StartTime