Blaster.NET

Blaster.NET is a .NET 10 port of AlliedModders Blaster for querying Valve game servers and collecting aggregated stats.

It includes:

• Blaster.Valve: Valve master/server query protocol support (SteamKit2 + A2S)
• Blaster.Batch: concurrent worker/batch processing
• Blaster.CLI: command-line server query tool (JSON output)
• Blaster.AmStats: stats collector that writes aggregates to an existing MySQL database
• Blaster.Tests: unit and integration tests

Differences from the Golang version

• Ported from Go to C#,
• Switched from old master server to GMS server query with SteamKit
• Added support for more games / mods
• Updated CS:GO to its new app id and re-enabled it for querying
• Filtered out SDR "fakeip" servers from querying by default; opt-in querying now supported via --include-fakeip
• Filtered redirect/spam "server farms" out of master results (configurable via --max-servers-per-host)
• Added valve_game_id and last_seen columns to AmStats schema

Requirements

• .NET SDK 10
• Network access to Steam/Valve query endpoints
• For Blaster.AmStats: reachable MySQL database with the expected schema already created

Build and test

dotnet build
dotnet test

Run only integration tests:

dotnet test --filter "Category=Integration"

See TESTING.md for running unit vs integration tests and the required environment variables.

Standalone executables

Build optimized, self-contained Linux executables (no .NET runtime required):

# AmStats with trimming and ReadyToRun optimization
dotnet publish src/Blaster.AmStats -c Release -r linux-x64 --self-contained \
  -p:PublishSingleFile=true -p:PublishReadyToRun=true \
  -p:DebugType=none -p:DebugSymbols=false

# CLI with trimming and ReadyToRun optimization
dotnet publish src/Blaster.CLI -c Release -r linux-x64 --self-contained \
  -p:PublishSingleFile=true -p:PublishReadyToRun=true \
  -p:DebugType=none -p:DebugSymbols=false

For Steam-backed integration tests, set credentials via environment variables first:

set BLASTER_TEST_STEAM_USERNAME=your_steam_username
set BLASTER_TEST_STEAM_PASSWORD=your_steam_password
dotnet test --filter "Category=Integration"

CLI usage (Blaster.CLI)

Run help:

dotnet run --project src/Blaster.CLI -- --help

Basic query:

dotnet run --project src/Blaster.CLI -- --appids 240 --steam-username myuser --steam-password mypass

Multiple app IDs:

dotnet run --project src/Blaster.CLI -- --appids 240 440 730

Output modes:

dotnet run --project src/Blaster.CLI -- --appids 240 --format list
dotnet run --project src/Blaster.CLI -- --appids 240 --format map
dotnet run --project src/Blaster.CLI -- --appids 240 --format lines

Performance/behavior flags:

dotnet run --project src/Blaster.CLI -- --appids 240 --concurrency 20
dotnet run --project src/Blaster.CLI -- --appids 240 --no-info
dotnet run --project src/Blaster.CLI -- --appids 240 --no-rules

Using environment variables instead of CLI secrets:

set BLASTER_STEAM_USERNAME=myuser
set BLASTER_STEAM_PASSWORD=mypass
dotnet run --project src/Blaster.CLI -- --appids 240 --format list

Using the Steam Web API transport:

dotnet run --project src/Blaster.CLI -- --appids 240 --transport web-api --steam-webapi-key YOURKEYHERE
# or via environment variable:
set BLASTER_STEAM_WEBAPI_KEY=YOURKEYHERE
dotnet run --project src/Blaster.CLI -- --appids 240 --transport web-api

CLI options

Option	Description
--appids <IDS...>	Required. One or more Valve app IDs
--format <list|map|lines>	Output format (default: list)
--transport <steam|web-api>	Master-server transport (default: steam); see Master server transports
--steam-username <U>	Steam username (or BLASTER_STEAM_USERNAME); required for steam transport
--steam-password <P>	Steam password (or BLASTER_STEAM_PASSWORD); required for steam transport
--steam-webapi-key <K>	Steam Web API key (or BLASTER_STEAM_WEBAPI_KEY); required for web-api transport
--log-level <LEVEL>	Log level: trace, debug, info, warn, error, critical (default: info); trace surfaces detailed per-app fan-out query statistics
--no-info	Skip A2S_INFO queries
--no-rules	Skip A2S_RULES queries
--include-fakeip	Opt-in: also query SDR/fake-IP (169.254.*) servers via QueryByFakeIP instead of dropping them; see Fake-IP / SDR servers
--concurrency <N>	Max concurrent server queries (default: 20)
--max-servers-per-host <N>	Drop IPs advertising more than N servers as redirect/spam farms (or BLASTER_MAX_SERVERS_PER_HOST; default: 100; 0 disables); see Spam-farm filtering
--help	Show help

Stats collector usage (Blaster.AmStats)

Run help:

dotnet run --project src/Blaster.AmStats -- --help

Run collection:

dotnet run --project src/Blaster.AmStats -- --game hl1 --config config.yml --steam-username myuser --steam-password mypass
dotnet run --project src/Blaster.AmStats -- --game hl2 --config config.yml

Enable debug logging:

dotnet run --project src/Blaster.AmStats -- --game hl1 --config config.yml --log-level debug

AmStats options

Option	Description
--game <hl1|hl2>	Required. Game to collect stats for
--config <PATH>	Config file path (default: config.yml)
--transport <steam|web-api>	Master-server transport (overrides config key steam.transport); see Master server transports
--steam-username <U>	Steam username (overrides config/env); required for steam transport
--steam-password <P>	Steam password (overrides config/env); required for steam transport
--steam-webapi-key <K>	Steam Web API key (overrides config/env); required for web-api transport
--log-level <LEVEL>	Log level: trace, debug, info, warn, error, critical (default: info); trace surfaces detailed per-app fan-out query statistics
--include-fakeip	Opt-in: also query SDR/fake-IP (169.254.*) servers via QueryByFakeIP instead of dropping them (config: fakeip.enabled, env: BLASTER_FAKEIP); see Fake-IP / SDR servers
--help	Show help

Config file (config.yml)

Create a YAML file like:

database:
  host: localhost
  username: root
  password: YourPassword
  dbname: blaster_stats
steam:
  username: myuser
  password: mypass
  # Optional — choose master-server transport. Values: steam (default), web-api
  # transport: web-api
  # webapi_key: YOURKEYHERE
  # Optional — drop IPs advertising more than this many servers as redirect/spam farms
  # (default: 100; 0 disables). See "Spam-farm filtering" below.
  # max_servers_per_host: 100
fakeip:
  # Optional — set to true to query SDR/fake-IP servers via QueryByFakeIP
  # enabled: false

--game maps to:

• hl1 -> game id 1
• hl2 -> game id 2

Steam credentials, transport settings, and fake-IP behaviour for runtime can come from:

1. CLI args (--steam-username, --steam-password, --transport, --steam-webapi-key, --include-fakeip)
2. Config file (steam.username, steam.password, steam.transport, steam.webapi_key, fakeip.enabled) for AmStats
3. Environment variables (BLASTER_STEAM_USERNAME, BLASTER_STEAM_PASSWORD, BLASTER_STEAM_TRANSPORT, BLASTER_STEAM_WEBAPI_KEY, BLASTER_FAKEIP)

Fake-IP / SDR servers

Some Valve game servers are hosted behind Steam Datagram Relay (SDR) and advertise a link-local "fake IP" address in the 169.254.0.0/16 range. These addresses are unreachable over ordinary UDP, so Blaster drops them by default. Passing --include-fakeip opts in to querying them via GameServers.QueryByFakeIP, using whichever transport is selected (Steam CM connection or Web API). This fake-IP pass runs concurrently with the normal UDP A2S pass, so overall collection time is not significantly increased. For some games — TF2 is a prominent example — fake-IP servers are a large fraction of the total server population, and omitting them will materially under-count results.

Spam-farm filtering

Valve master lists are heavily polluted with redirect "farms": a single IP answering on thousands of sequential ports, each impersonating a server, to flood the list and funnel players. Blaster flags these during the master fan-out, using the (harder-to-spoof) counts the GMS reports — no extra A2S query — with two signals:

• Port farm: an IP advertising more than max-servers-per-host servers (default 100) is treated as one operator stuffing the list, and the whole host is dropped.
• Impossible player count: a server reporting more than 130 players is dropped on its own (no real Valve game is realistically this full — most cap at 64, TF2 ~100, GMod ~128), but its host is only condemned if it also trips the port-farm threshold, so a lone faker on a shared hosting IP doesn't take its legitimate neighbours down with it.

Flagged hosts are dropped before they reach the output, and fed back into the fan-out as a master-server NOR exclusion so deeper queries stop returning them.

SDR / fake-IP (169.254.0.0/16) servers are exempt from this filter: they legitimately share addresses across the SDR network, so they are never counted toward the per-host threshold or culled. (Whether they are queried at all is controlled separately by --include-fakeip; see Fake-IP / SDR servers.)

Configuration:

• CLI: --max-servers-per-host <N> or BLASTER_MAX_SERVERS_PER_HOST.
• AmStats: steam.max_servers_per_host in config.yml or BLASTER_MAX_SERVERS_PER_HOST (no CLI flag).
• Default is 100; set to 0 to disable the filter entirely.

Master server transports

Blaster.NET supports two transports for querying the Steam master server:

• steam (default): Opens a live SteamKit2 connection to the Steam Game Management Server (GMS) using a Steam account. Requires --steam-username / --steam-password (or their config/env equivalents).
• web-api: Queries the Steam Web API (IGameServersService/GetServerList) over HTTPS instead of a direct Steam connection. Requires a Steam Web API key via --steam-webapi-key (or BLASTER_STEAM_WEBAPI_KEY). No Steam account is needed. The Web API is subject to a documented rate limit of approximately 200 requests per 5 minutes; the client enforces a minimum 1.5-second interval between requests and handles HTTP 429 responses gracefully by honoring the Retry-After header before retrying.